diff --git a/client/src/mobile/screens/admin/MAdmin.tsx b/client/src/mobile/screens/admin/MAdmin.tsx
index 5f4923281..5130ba5f2 100644
--- a/client/src/mobile/screens/admin/MAdmin.tsx
+++ b/client/src/mobile/screens/admin/MAdmin.tsx
@@ -230,12 +230,14 @@ export default function MAdmin() {
           }}
           collabFeatures={collabFeatures}
           onToggleCollabFeature={async (key: string) => {
-            const next = { ...collabFeatures, [key]: !collabFeatures[key] }
-            setCollabFeatures(next)
+            const previous = collabFeatures[key]
+            setCollabFeatures({ ...collabFeatures, [key]: !previous })
             try {
-              await adminApi.updateCollabFeatures({ [key]: next[key] })
+              await adminApi.updateCollabFeatures({ [key]: !previous })
             } catch {
-              setCollabFeatures(collabFeatures)
+              // Only this key rolls back — a slower request must not undo a toggle
+              // the admin made in the meantime.
+              setCollabFeatures(prev => ({ ...prev, [key]: previous }))
             }
           }}
         />
diff --git a/client/src/mobile/screens/dashboard/MNewTripSheet.tsx b/client/src/mobile/screens/dashboard/MNewTripSheet.tsx
index 654e054e0..e046b0a54 100644
--- a/client/src/mobile/screens/dashboard/MNewTripSheet.tsx
+++ b/client/src/mobile/screens/dashboard/MNewTripSheet.tsx
@@ -89,6 +89,13 @@ export default function MNewTripSheet({ open, trip, onClose, onSave, onCoverUpda
     setError('')
   }, [trip, open])
 
+  // The local file preview is a blob url; release it once a new cover replaces it
+  // or the sheet goes away. Server and Unsplash urls are left alone.
+  useEffect(() => {
+    if (!coverPreview?.startsWith('blob:')) return
+    return () => { URL.revokeObjectURL(coverPreview) }
+  }, [coverPreview])
+
   // Moving the start keeps the trip length (same rule as TripFormModal).
   const changeStart = (value: string) => {
     if (value && endDate && startDate && endDate >= startDate) {
diff --git a/client/src/mobile/screens/journey/MJourneyDetail.tsx b/client/src/mobile/screens/journey/MJourneyDetail.tsx
index 012c17dd3..a98175d3c 100644
--- a/client/src/mobile/screens/journey/MJourneyDetail.tsx
+++ b/client/src/mobile/screens/journey/MJourneyDetail.tsx
@@ -135,7 +135,9 @@ export default function MJourneyDetail() {
   const [uploading, setUploading] = useState(false)
 
   useEffect(() => {
-    (async () => {
+    let active = true
+    const ac = new AbortController()
+    ;(async () => {
       try {
         const addonsData = await addonsApi.enabled()
         const enabled = (addonsData.addons || []).filter(
@@ -144,13 +146,14 @@ export default function MJourneyDetail() {
         const connected: { id: string; name: string }[] = []
         for (const p of enabled) {
           try {
-            const res = await fetch(`/api/integrations/memories/${p.id}/status`, { credentials: 'include' })
+            const res = await fetch(`/api/integrations/memories/${p.id}/status`, { credentials: 'include', signal: ac.signal })
             if (res.ok && (await res.json()).connected) connected.push({ id: p.id, name: p.name })
           } catch { /* provider stays hidden */ }
         }
-        setAvailableProviders(connected)
+        if (active) setAvailableProviders(connected)
       } catch { /* no providers */ }
     })()
+    return () => { active = false; ac.abort() }
   }, [])
 
   const handleGalleryUpload = async (e: React.ChangeEvent<HTMLInputElement>) => {
diff --git a/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx b/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx
index 33f4db055..9692cb6ab 100644
--- a/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx
+++ b/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx
@@ -101,6 +101,11 @@ export default function MJourneyEntrySheet({
     [addons],
   )
 
+  // Minting the preview inside the tile markup would hand out a fresh blob URL on
+  // every keystroke in the story field, and nothing would ever release them.
+  const pendingPreviews = useMemo(() => pendingFiles.map(f => URL.createObjectURL(f)), [pendingFiles])
+  useEffect(() => () => { pendingPreviews.forEach(url => URL.revokeObjectURL(url)) }, [pendingPreviews])
+
   useEffect(() => {
     if (readOnly) return
     // App.tsx loads the addon list on boot, so this only reacts to it. Kicking off
@@ -536,13 +541,13 @@ export default function MJourneyEntrySheet({
                   <button
                     type="button"
                     onClick={() => {
-                      setPhotos(prev => {
-                        const next = [...prev]
-                        const [moved] = next.splice(idx, 1)
-                        next.unshift(moved)
-                        next.forEach((ph, i) => { journeyApi.updatePhoto(ph.id, { sort_order: i }).catch(() => {}) })
-                        return next
-                      })
+                      // The PATCHes stay outside the updater — StrictMode invokes it
+                      // twice in dev and would send the whole batch a second time.
+                      const next = [...photos]
+                      const [moved] = next.splice(idx, 1)
+                      next.unshift(moved)
+                      setPhotos(next)
+                      next.forEach((ph, i) => { journeyApi.updatePhoto(ph.id, { sort_order: i }).catch(() => {}) })
                     }}
                     className="absolute bottom-[3px] left-[3px] rounded-full bg-black/60 px-[6px] py-[1px] font-geist text-[0.5rem] font-bold text-white"
                   >
@@ -568,9 +573,9 @@ export default function MJourneyEntrySheet({
                 )}
               </div>
             ))}
-            {pendingFiles.map((f, i) => (
+            {pendingFiles.map((_, i) => (
               <div key={`pending-${i}`} className="relative h-16 w-16 overflow-hidden rounded-[13px]">
-                <img src={URL.createObjectURL(f)} alt="" className="h-full w-full object-cover" />
+                <img src={pendingPreviews[i]} alt="" className="h-full w-full object-cover" />
                 <button
                   type="button"
                   onClick={() => setPendingFiles(prev => prev.filter((_, j) => j !== i))}
diff --git a/client/src/mobile/screens/journey/MJourneySettingsSheet.tsx b/client/src/mobile/screens/journey/MJourneySettingsSheet.tsx
index db7df0769..4049ee80d 100644
--- a/client/src/mobile/screens/journey/MJourneySettingsSheet.tsx
+++ b/client/src/mobile/screens/journey/MJourneySettingsSheet.tsx
@@ -131,6 +131,27 @@ export default function MJourneySettingsSheet({
     }
   }
 
+  const copyShareUrl = async () => {
+    try {
+      if (navigator.clipboard && window.isSecureContext) {
+        await navigator.clipboard.writeText(shareUrl)
+      } else {
+        // Fallback for non-secure contexts (plain HTTP) where navigator.clipboard is unavailable
+        const ta = document.createElement('textarea')
+        ta.value = shareUrl
+        ta.style.position = 'fixed'
+        ta.style.left = '-9999px'
+        document.body.appendChild(ta)
+        ta.focus()
+        ta.select()
+        document.execCommand('copy')
+        document.body.removeChild(ta)
+      }
+      setCopied(true)
+      setTimeout(() => setCopied(false), 2000)
+    } catch { /* ignore */ }
+  }
+
   const toggleSharePerm = async (key: 'share_timeline' | 'share_gallery' | 'share_map') => {
     if (!shareLink) return
     const updated = { ...shareLink, [key]: !shareLink[key] }
@@ -333,11 +354,7 @@ export default function MJourneySettingsSheet({
               <span className="min-w-0 flex-1 truncate font-geist text-[0.6875rem] text-m-muted">{shareUrl}</span>
               <button
                 type="button"
-                onClick={() => {
-                  navigator.clipboard.writeText(shareUrl)
-                  setCopied(true)
-                  setTimeout(() => setCopied(false), 2000)
-                }}
+                onClick={copyShareUrl}
                 className="flex-none rounded-full bg-m-act px-3 py-[5px] font-geist text-[0.65625rem] font-bold text-m-actfg"
               >
                 {copied ? t('journey.share.copied') : t('journey.share.copy')}
diff --git a/client/src/mobile/screens/settings/MSettingsAccount.tsx b/client/src/mobile/screens/settings/MSettingsAccount.tsx
index 098245ed5..f1137a268 100644
--- a/client/src/mobile/screens/settings/MSettingsAccount.tsx
+++ b/client/src/mobile/screens/settings/MSettingsAccount.tsx
@@ -18,6 +18,7 @@ import {
 } from 'lucide-react'
 import { useNavigate, useSearchParams } from 'react-router'
 import { startRegistration } from '@simplewebauthn/browser'
+import { escapeHtml } from '@trek/shared'
 import { useTranslation } from '../../../i18n'
 import { useAuthStore } from '../../../store/authStore'
 import { useToast } from '../../../components/shared/Toast'
@@ -136,7 +137,7 @@ export default function MSettingsAccount() {
   const printBackupCodes = () => {
     const html = `<!doctype html><html><head><meta charset="utf-8"/><title>TREK MFA Backup Codes</title>
       <style>body{font-family:Arial,sans-serif;padding:32px}h1{font-size:20px}pre{font-size:16px;line-height:1.6}</style>
-      </head><body><h1>TREK MFA Backup Codes</h1><p>${new Date().toLocaleString()}</p><pre>${backupCodesText}</pre></body></html>`
+      </head><body><h1>TREK MFA Backup Codes</h1><p>${escapeHtml(new Date().toLocaleString())}</p><pre>${escapeHtml(backupCodesText)}</pre></body></html>`
     const w = window.open('', '_blank', 'width=900,height=700')
     if (!w) return
     w.document.open()
diff --git a/client/src/mobile/screens/settings/MSettingsAppearance.tsx b/client/src/mobile/screens/settings/MSettingsAppearance.tsx
index 68ce034f3..609030d77 100644
--- a/client/src/mobile/screens/settings/MSettingsAppearance.tsx
+++ b/client/src/mobile/screens/settings/MSettingsAppearance.tsx
@@ -85,6 +85,9 @@ export default function MSettingsAppearance() {
 
   const [cfg, setCfg] = useState<AppearanceConfig>(() => normalizeAppearance(settings.appearance))
   const persistTimer = useRef<number | undefined>(undefined)
+  // What the pending timer would have written, so leaving the screen inside the
+  // debounce window still saves instead of silently dropping the change.
+  const pendingWrite = useRef<AppearanceConfig | null>(null)
 
   // Re-sync when settings change elsewhere (server reconcile / another tab).
   useEffect(() => {
@@ -92,8 +95,11 @@ export default function MSettingsAppearance() {
   }, [settings.appearance])
 
   useEffect(() => () => {
-    if (persistTimer.current) window.clearTimeout(persistTimer.current)
-  }, [])
+    if (!persistTimer.current) return
+    window.clearTimeout(persistTimer.current)
+    // The component is gone, so a failure has nowhere to be shown.
+    if (pendingWrite.current) updateSetting('appearance', pendingWrite.current).catch(() => {})
+  }, [updateSetting])
 
   const isDark =
     settings.dark_mode === true ||
@@ -106,7 +112,9 @@ export default function MSettingsAppearance() {
     setCfg(next)
     applyAppearance({ darkMode: settings.dark_mode, appearance: next, isSharedPage: false })
     if (persistTimer.current) window.clearTimeout(persistTimer.current)
+    pendingWrite.current = next
     persistTimer.current = window.setTimeout(() => {
+      pendingWrite.current = null
       updateSetting('appearance', next).catch((e: unknown) =>
         toast.error(e instanceof Error ? e.message : t('common.error')),
       )
diff --git a/client/src/mobile/screens/settings/MSettingsNotifications.tsx b/client/src/mobile/screens/settings/MSettingsNotifications.tsx
index b274b40e0..9032f9e45 100644
--- a/client/src/mobile/screens/settings/MSettingsNotifications.tsx
+++ b/client/src/mobile/screens/settings/MSettingsNotifications.tsx
@@ -127,7 +127,13 @@ export default function MSettingsNotifications() {
     try {
       await notificationsApi.updatePreferences(updated)
     } catch {
-      setMatrix((m) => (m ? { ...m, preferences: matrix.preferences } : m))
+      // Only this cell rolls back — restoring the whole snapshot would also undo a
+      // toggle the user made while this request was in flight.
+      setMatrix((m) => (m ? {
+        ...m,
+        preferences: { ...m.preferences, [eventType]: { ...m.preferences[eventType], [channel]: current } },
+      } : m))
+      toast.error(t('common.error'))
     } finally {
       setSaving(false)
     }
diff --git a/client/src/mobile/screens/trip/plan/MPlanTimeline.tsx b/client/src/mobile/screens/trip/plan/MPlanTimeline.tsx
index dbdb71bcb..dc053838b 100644
--- a/client/src/mobile/screens/trip/plan/MPlanTimeline.tsx
+++ b/client/src/mobile/screens/trip/plan/MPlanTimeline.tsx
@@ -417,8 +417,8 @@ function TimelineHeader({ tl, dayLabel, openLabel, onOpenDay }: {
 
 /** Icon-coded like the demo, colour-tinted per the audit (green in / red out). */
 function HotelChipIcon({ variant }: { variant: 'checkout' | 'checkin' | 'stay' }) {
-  if (variant === 'checkout') return <LogOut size={12} strokeWidth={2.2} className="text-[#D6273B]" />
-  if (variant === 'checkin') return <LogIn size={12} strokeWidth={2.2} className="text-[#3BA55C]" />
+  if (variant === 'checkout') return <LogOut size={12} strokeWidth={2.2} className="text-[color:var(--m-st-danger)]" />
+  if (variant === 'checkin') return <LogIn size={12} strokeWidth={2.2} className="text-[color:var(--m-st-confirmed)]" />
   return <BedDouble size={12} strokeWidth={2.2} className="text-m-muted" />
 }
 
diff --git a/client/src/mobile/screens/trip/sheets/MCostSheet.tsx b/client/src/mobile/screens/trip/sheets/MCostSheet.tsx
index 8e3108bcb..70262ed0e 100644
--- a/client/src/mobile/screens/trip/sheets/MCostSheet.tsx
+++ b/client/src/mobile/screens/trip/sheets/MCostSheet.tsx
@@ -12,6 +12,7 @@ import { useExchangeRates } from '../../../../hooks/useExchangeRates'
 import { formatMoney, localizeAmountInput, cleanAmount } from '../../../../utils/formatters'
 import { SYMBOLS, SPLIT_COLORS, currenciesWith } from '../../../../components/Budget/BudgetPanel.constants'
 import { COST_CATEGORY_LIST, catMeta } from '../../../../components/Budget/costsCategories'
+import { localToday } from '../../../../components/Planner/today'
 import { calculateTicketShares, hasTicketSplit, NOTE_MAX, readTicketItems, readUserNote, splitEqualShares, writeTicketItems, type TicketItem } from '../../../../components/Budget/CostsPanel.helpers'
 import type { ExpensePrefill } from '../../../../components/Budget/CostsPanel'
 import { payersBalanced, rebalancePayers } from '../../../../components/Budget/CostsPanel.helpers'
@@ -72,7 +73,7 @@ export default function MCostSheet({ tripId, base, people, me, editing, prefill,
   const [catOpen, setCatOpen] = useState(false)
   const [note, setNote] = useState(() => readUserNote(editing))
   const [currency, setCurrency] = useState((editing?.currency || base).toUpperCase())
-  const [day, setDay] = useState(editing?.expense_date || new Date().toISOString().slice(0, 10))
+  const [day, setDay] = useState(editing?.expense_date || localToday())
   const [total, setTotal] = useState<string>(() => {
     if (editing) return editing.total_price ? String(cleanAmount(editing.total_price)) : ''
     if (prefill?.amount != null) return String(prefill.amount)
@@ -296,6 +297,7 @@ export default function MCostSheet({ tripId, base, people, me, editing, prefill,
         <span
           style={{
             width: size, height: size, borderRadius: '50%', background: SPLIT_COLORS[idx % SPLIT_COLORS.length].gradient,
+            // theme-lint-disable — white initial on the member's tint, and the glyph scales with the avatar
             color: '#fff', display: 'grid', placeItems: 'center', fontSize: size * 0.4, fontWeight: 700, flexShrink: 0, opacity: dim ? 0.45 : 1,
           }}
         >
@@ -608,7 +610,7 @@ export default function MCostSheet({ tripId, base, people, me, editing, prefill,
                   {participants.size > 0 && t('costs.splitSummary', { count: participants.size, amount: sym(currency) + each.toFixed(2) })}
                 </span>
               ) : (
-                <span className={`font-semibold ${customBalanced ? 'text-[#16a34a]' : 'text-[color:var(--m-st-danger)]'}`}>
+                <span className={`font-semibold ${customBalanced ? 'text-[color:var(--m-st-confirmed)]' : 'text-[color:var(--m-st-danger)]'}`}>
                   {customBalanced
                     ? t('costs.splitSummary', { count: participants.size, amount: sym(currency) + each.toFixed(2) })
                     : `${sym(currency)}${splitSum.toFixed(2)} / ${sym(currency)}${totalNum.toFixed(2)}`}
diff --git a/client/src/mobile/screens/trip/sheets/MReservationSheet.tsx b/client/src/mobile/screens/trip/sheets/MReservationSheet.tsx
index de9bba8b5..90a85de11 100644
--- a/client/src/mobile/screens/trip/sheets/MReservationSheet.tsx
+++ b/client/src/mobile/screens/trip/sheets/MReservationSheet.tsx
@@ -4,6 +4,7 @@ import MSheet from '../../../components/MSheet'
 import { useAddonStore } from '../../../../store/addonStore'
 import { useTranslation } from '../../../../i18n'
 import { resolveDayId } from '../../../../utils/formatters'
+import { parseReservationMetadata } from '../../../../utils/flightLegs'
 import { typeToCostCategory } from '@trek/shared'
 import CustomSelect from '../../../../components/shared/CustomSelect'
 import CustomTimePicker from '../../../../components/shared/CustomTimePicker'
@@ -86,7 +87,7 @@ export default function MReservationSheet({ planner, onOpenExpense }: MReservati
 
     const res = editingReservation
     if (res) {
-      const meta = typeof res.metadata === 'string' ? JSON.parse(res.metadata || '{}') : (res.metadata || {})
+      const meta = parseReservationMetadata(res)
       const rawEnd = res.reservation_end_time || ''
       let endDate = '', endTime = rawEnd
       if (rawEnd.includes('T')) { endDate = rawEnd.split('T')[0]; endTime = rawEnd.split('T')[1]?.slice(0, 5) || '' }
diff --git a/client/src/mobile/screens/trip/tabs/MFileLightbox.tsx b/client/src/mobile/screens/trip/tabs/MFileLightbox.tsx
index c90886568..79b458f5a 100644
--- a/client/src/mobile/screens/trip/tabs/MFileLightbox.tsx
+++ b/client/src/mobile/screens/trip/tabs/MFileLightbox.tsx
@@ -37,8 +37,14 @@ export default function MFileLightbox({ files, index, onIndexChange, onClose, t
   const fileMimeType = file?.mime_type
 
   useEffect(() => {
+    // Swiping is faster than the resource-token round trip, so a stale token must
+    // not overwrite the file the user is looking at now.
+    let cancelled = false
     setImgSrc('')
-    if (fileUrl && !isVideo(fileMimeType)) getAuthUrl(fileUrl, 'download').then(setImgSrc)
+    if (fileUrl && !isVideo(fileMimeType)) {
+      getAuthUrl(fileUrl, 'download').then(url => { if (!cancelled) setImgSrc(url) })
+    }
+    return () => { cancelled = true }
   }, [fileUrl, fileMimeType])
 
   const hasPrev = index > 0
diff --git a/client/src/mobile/screens/trip/tabs/MTodoListTab.tsx b/client/src/mobile/screens/trip/tabs/MTodoListTab.tsx
index 028e442a5..3e6c750eb 100644
--- a/client/src/mobile/screens/trip/tabs/MTodoListTab.tsx
+++ b/client/src/mobile/screens/trip/tabs/MTodoListTab.tsx
@@ -5,6 +5,7 @@ import { useAuthStore } from '../../../../store/authStore'
 import { useTranslation } from '../../../../i18n'
 import { avatarSrc } from '../../../../utils/avatarSrc'
 import { formatDate } from '../../../../utils/formatters'
+import { localToday } from '../../../../components/Planner/today'
 import type { TodoItem, TripMember } from '../../../../types'
 import type { TripPlanner } from '../MTripShell'
 import { TabScroller } from './tabChrome'
@@ -39,7 +40,9 @@ export default function MTodoListTab({ planner }: { planner: TripPlanner }) {
   const [editingItemId, setEditingItemId] = useState<number | null>(null)
   const [creatingTask, setCreatingTask] = useState(false)
 
-  const today = useMemo(() => new Date().toISOString().slice(0, 10), [])
+  // The user's calendar day, not UTC's — an overdue task must turn overdue at
+  // the traveller's midnight, not eight hours either side of it.
+  const today = useMemo(() => localToday(), [])
   const categories = useMemo(() => todoCategories(items), [items])
   const counts = todoCounts(items, currentUserId, today)
   const rows = useMemo(
diff --git a/client/src/mobile/screens/trip/tabs/costsModel.ts b/client/src/mobile/screens/trip/tabs/costsModel.ts
index 64f612d37..03a13528c 100644
--- a/client/src/mobile/screens/trip/tabs/costsModel.ts
+++ b/client/src/mobile/screens/trip/tabs/costsModel.ts
@@ -215,8 +215,12 @@ export interface CsvBuildOptions {
 /** Ports `CostsPanel.tsx`'s `handleExportCsv` row-building 1:1; the Blob/download is a DOM concern left to the caller. */
 export function buildCostsCsv(items: BudgetItem[], opts: CsvBuildOptions): { filename: string; content: string } {
   const sep = ';'
+  // A cell starting with =, +, -, @, TAB or CR is evaluated as a formula by Excel
+  // and Sheets, and the name/note columns are free text any trip member can write.
+  // Mirrors the same guard in `CostsPanel.tsx`'s exporter.
   const esc = (v: unknown) => {
-    const s = String(v ?? '')
+    let s = String(v ?? '')
+    if (/^[=+\-@\t\r]/.test(s)) s = "'" + s
     return s.includes(sep) || s.includes('"') || s.includes('\n') ? '"' + s.replace(/"/g, '""') + '"' : s
   }
   const fmtDate = (iso: string) => {