diff --git a/client/src/components/Collab/CollabNotes.tsx b/client/src/components/Collab/CollabNotes.tsx
index 95e540576..1eb336f2a 100644
--- a/client/src/components/Collab/CollabNotes.tsx
+++ b/client/src/components/Collab/CollabNotes.tsx
@@ -18,6 +18,7 @@ import type { User } from '../../types'
 import type { CollabNote } from './CollabNotes.types'
 import { announceNoteFilesChanged, useCollabNotesData } from './useCollabNotesData'
 import { FONT, NOTE_COLORS } from './CollabNotes.constants'
+import { buildCategoryColorMap } from './collabModel'
 import { NoteFormModal } from './CollabNotesFormModal'
 import { CategorySettingsModal } from './CollabNotesCategorySettingsModal'
 import { NoteCard } from './CollabNotesCard'
@@ -68,13 +69,10 @@ function useCollabNotes({ tripId, currentUser }: CollabNotesProps) {
   }
 
   // Category colors: from notes first, then from empty categories
-  const categoryColors = useMemo(() => {
-    const map = { ...emptyCategories }
-    for (const n of notes) {
-      if (n.category && n.color) map[n.category] = n.color
-    }
-    return map
-  }, [notes, emptyCategories])
+  const categoryColors = useMemo(
+    () => ({ ...emptyCategories, ...buildCategoryColorMap(notes) }),
+    [notes, emptyCategories]
+  )
 
   const getCategoryColor = (cat) => {
     if (!cat) return NOTE_COLORS[0].value
diff --git a/client/src/components/Collab/collabModel.ts b/client/src/components/Collab/collabModel.ts
index 59c2b6b3e..f58d2c2c4 100644
--- a/client/src/components/Collab/collabModel.ts
+++ b/client/src/components/Collab/collabModel.ts
@@ -150,13 +150,16 @@ export interface CollabNoteData {
 /** Category swatch palette, the same 6 hex values the desktop picker uses. */
 export const NOTE_COLORS = ['#6366f1', '#ef4444', '#f59e0b', '#10b981', '#3b82f6', '#8b5cf6'];
 
-/** One color per category, taken from whatever any note in that category
- *  already has stored (every note in a category is written with the same
- *  color at create time, so first-seen === all-seen in practice). */
-export function buildCategoryColorMap(notes: CollabNoteData[]): Record<string, string> {
+/** One color per category, taken from the notes in it, for the desktop panel and the
+ *  phone tab alike. Every note in a category is normally written with the same color,
+ *  but a recolour that failed halfway or a note written over the API can leave two;
+ *  then the last one in list order wins. */
+export function buildCategoryColorMap(
+  notes: readonly { category?: string | null; color?: string | null }[]
+): Record<string, string> {
   const map: Record<string, string> = {};
   for (const n of notes) {
-    if (n.category && n.color && !map[n.category]) map[n.category] = n.color;
+    if (n.category && n.color) map[n.category] = n.color;
   }
   return map;
 }
diff --git a/client/tests/unit/mobile/trip/collabModel.test.ts b/client/tests/unit/mobile/trip/collabModel.test.ts
index e676256df..4ea2f72c6 100644
--- a/client/tests/unit/mobile/trip/collabModel.test.ts
+++ b/client/tests/unit/mobile/trip/collabModel.test.ts
@@ -179,14 +179,23 @@ describe('collabModel — chat', () => {
 });
 
 describe('collabModel — notes', () => {
-  it('FE-MOB-CLBM-011: buildCategoryColorMap keeps the first colour seen per category', () => {
+  it('FE-MOB-CLBM-011: buildCategoryColorMap keeps the last colour seen per category', () => {
     const notes = [
       note({ id: 1, category: 'Ideas', color: '#ef4444' }),
       note({ id: 2, category: 'Ideas', color: '#10b981' }),
       note({ id: 3, category: 'Food', color: null }),
       note({ id: 4, category: null, color: '#3b82f6' }),
     ];
-    expect(buildCategoryColorMap(notes)).toEqual({ Ideas: '#ef4444' });
+    expect(buildCategoryColorMap(notes)).toEqual({ Ideas: '#10b981' });
+  });
+
+  it('FE-MOB-CLBM-023: a category whose notes disagree takes the colour the desktop panel shows', () => {
+    // A category recolour that failed halfway leaves its notes on two colours.
+    const notes = [
+      note({ id: 1, category: 'Ideas', color: '#ef4444' }),
+      note({ id: 2, category: 'Ideas', color: '#10b981' }),
+    ];
+    expect(buildCategoryColorMap(notes)).toEqual({ Ideas: '#10b981' });
   });
 
   it('FE-MOB-CLBM-012: getCategoryColor round-robins fresh categories onto the palette', () => {