diff --git a/src/renderer/src/App.tsx b/src/renderer/src/App.tsx
index 643b6497e5d..0795d6221a3 100644
--- a/src/renderer/src/App.tsx
+++ b/src/renderer/src/App.tsx
@@ -1416,7 +1416,9 @@ function App(): React.JSX.Element {
         hideWorkspacesFromOtherDevices,
         alwaysShowDefaultBranchWorkspace,
         showDotfilesByWorktree,
-        filterRepoIds,
+        // Why: the store keeps this readonly for identity stability, but PersistedUI crosses to
+        // main, which owns a mutable array — copy at the boundary rather than widening the wire type.
+        filterRepoIds: [...filterRepoIds],
         // Why (#9002): activeView is deliberately NOT included here. It used to
         // ride this same 150ms writer (#8265), which meant every top-level view
         // switch scheduled a full durable-state save. The narrow preference
diff --git a/src/renderer/src/components/sidebar/add-repo-skip-finalization.ts b/src/renderer/src/components/sidebar/add-repo-skip-finalization.ts
index 4161f3bb6f9..7c9c69357ce 100644
--- a/src/renderer/src/components/sidebar/add-repo-skip-finalization.ts
+++ b/src/renderer/src/components/sidebar/add-repo-skip-finalization.ts
@@ -3,7 +3,7 @@ import { isDefaultBranchWorkspace } from './visible-worktrees'
 
 export type AddRepoSkipFinalizationState = {
   activeRepoId: string | null
-  filterRepoIds: string[]
+  filterRepoIds: readonly string[]
   showActiveOnly: boolean
   hideDefaultBranchWorkspace: boolean
   showSleepingWorkspaces: boolean
diff --git a/src/renderer/src/components/sidebar/visible-worktrees.ts b/src/renderer/src/components/sidebar/visible-worktrees.ts
index f85083db406..206d81dbe38 100644
--- a/src/renderer/src/components/sidebar/visible-worktrees.ts
+++ b/src/renderer/src/components/sidebar/visible-worktrees.ts
@@ -186,7 +186,7 @@ export function computeVisibleWorktreeIds(
   worktreesByRepo: Record<string, Worktree[]>,
   sortedIds: string[],
   opts: {
-    filterRepoIds: string[]
+    filterRepoIds: readonly string[]
     showSleepingWorkspaces: boolean
     tabsByWorktree: Record<string, Pick<TerminalTab, 'id'>[]> | null
     ptyIdsByTabId: Record<string, string[]> | null
diff --git a/src/renderer/src/store/slices/repo-filter-selection.ts b/src/renderer/src/store/slices/repo-filter-selection.ts
new file mode 100644
index 00000000000..65ae6d344a8
--- /dev/null
+++ b/src/renderer/src/store/slices/repo-filter-selection.ts
@@ -0,0 +1,10 @@
+// Why: catalog refreshes re-filter this on every fetch; six identity-sensitive subscribers
+// (App.tsx at the root among them) re-render on a new array even when nothing was pruned.
+export function retainValidFilterRepoIds(
+  filterRepoIds: readonly string[],
+  validRepoIds: ReadonlySet<string>
+): readonly string[] {
+  return filterRepoIds.every((repoId) => validRepoIds.has(repoId))
+    ? filterRepoIds
+    : filterRepoIds.filter((repoId) => validRepoIds.has(repoId))
+}
diff --git a/src/renderer/src/store/slices/repos.ts b/src/renderer/src/store/slices/repos.ts
index 25c53d3b481..01800b02896 100644
--- a/src/renderer/src/store/slices/repos.ts
+++ b/src/renderer/src/store/slices/repos.ts
@@ -48,6 +48,7 @@ import { isPathInsideOrEqual } from '../../../../shared/cross-platform-path'
 import { getRepoIdFromWorktreeId } from '../../../../shared/worktree-id'
 import { selectProjectGroupRemovalTargets } from './project-group-removal-targets'
 import { reconcileFetchedRepos } from './repo-identity-reconcile'
+import { retainValidFilterRepoIds } from './repo-filter-selection'
 import {
   mergeSshRepoReadoptions,
   reconcileReadoptedSshRepoRows,
@@ -2102,7 +2103,7 @@ export const createRepoSlice: StateCreator<AppState, [], [], RepoSlice> = (set,
             ? {}
             : { folderWorkspacePathStatuses: {} }),
           activeRepoId: s.activeRepoId && validRepoIds.has(s.activeRepoId) ? s.activeRepoId : null,
-          filterRepoIds: s.filterRepoIds.filter((projectId) => validRepoIds.has(projectId)),
+          filterRepoIds: retainValidFilterRepoIds(s.filterRepoIds, validRepoIds),
           setupScriptPromptDismissedRepoIds: filterSetupScriptPromptDismissalsToValidRepos(
             s.setupScriptPromptDismissedRepoIds,
             validRepoHostIdentities
@@ -2186,7 +2187,7 @@ export const createRepoSlice: StateCreator<AppState, [], [], RepoSlice> = (set,
           ...reconcileReadoptedSshWorktreeState(s, s.pendingSshRepoReadoptions),
           ...mergedProjectCompatibility,
           activeRepoId: s.activeRepoId && validRepoIds.has(s.activeRepoId) ? s.activeRepoId : null,
-          filterRepoIds: s.filterRepoIds.filter((projectId) => validRepoIds.has(projectId)),
+          filterRepoIds: retainValidFilterRepoIds(s.filterRepoIds, validRepoIds),
           setupScriptPromptDismissedRepoIds: filterSetupScriptPromptDismissalsToValidRepos(
             s.setupScriptPromptDismissedRepoIds,
             validRepoHostIdentities
@@ -2268,7 +2269,7 @@ export const createRepoSlice: StateCreator<AppState, [], [], RepoSlice> = (set,
         const validRepoHostIdentities = new Set(s.repos.map(getRepoHostIdentity))
         return {
           activeRepoId: s.activeRepoId && validRepoIds.has(s.activeRepoId) ? s.activeRepoId : null,
-          filterRepoIds: s.filterRepoIds.filter((projectId) => validRepoIds.has(projectId)),
+          filterRepoIds: retainValidFilterRepoIds(s.filterRepoIds, validRepoIds),
           setupScriptPromptDismissedRepoIds: filterSetupScriptPromptDismissalsToValidRepos(
             s.setupScriptPromptDismissedRepoIds,
             validRepoHostIdentities
diff --git a/src/renderer/src/store/slices/ui.ts b/src/renderer/src/store/slices/ui.ts
index 1bfa1d68d77..dbbc2977965 100644
--- a/src/renderer/src/store/slices/ui.ts
+++ b/src/renderer/src/store/slices/ui.ts
@@ -904,8 +904,8 @@ export type UISlice = {
   showDotfilesByWorktree: Record<string, boolean>
   setShowDotfilesForWorktree: (worktreeId: string, showDotfiles: boolean) => void
   toggleShowDotfilesForWorktree: (worktreeId: string) => void
-  filterRepoIds: string[]
-  setFilterRepoIds: (ids: string[]) => void
+  filterRepoIds: readonly string[]
+  setFilterRepoIds: (ids: readonly string[]) => void
   collapsedGroups: Set<string>
   toggleCollapsedGroup: (key: string) => void
   worktreeCardProperties: WorktreeCardProperty[]