diff --git a/src/renderer/src/components/sidebar/WorktreeList.tsx b/src/renderer/src/components/sidebar/WorktreeList.tsx
index ed36be3e4f8..a632336b9ae 100644
--- a/src/renderer/src/components/sidebar/WorktreeList.tsx
+++ b/src/renderer/src/components/sidebar/WorktreeList.tsx
@@ -91,6 +91,7 @@ import {
   PINNED_GROUP_KEY,
   buildRows,
   buildProjectGroupSidebarIndex,
+  findProjectGroupForRepo,
   getAmbiguousFolderWorkspaceSidebarIds,
   getProjectGroupHeaderKey,
   getProjectGroupMutationSelector,
@@ -1477,13 +1478,13 @@ const VirtualizedWorktreeViewport = React.memo(function VirtualizedWorktreeViewp
   scrollAnchorRef
 }: VirtualizedWorktreeViewportProps) {
   const activeWorkspaceExecutionHostId = useAppStore((s) => s.activeWorkspaceExecutionHostId)
+  const projectGroupSidebarIndex = useMemo(
+    () => buildProjectGroupSidebarIndex(projectGroups),
+    [projectGroups]
+  )
   const ambiguousFolderWorkspaceIds = useMemo(
-    () =>
-      getAmbiguousFolderWorkspaceSidebarIds(
-        buildProjectGroupSidebarIndex(projectGroups),
-        folderWorkspaces
-      ),
-    [folderWorkspaces, projectGroups]
+    () => getAmbiguousFolderWorkspaceSidebarIds(projectGroupSidebarIndex, folderWorkspaces),
+    [folderWorkspaces, projectGroupSidebarIndex]
   )
   const scrollRef = useRef<HTMLDivElement>(null)
   const suppressMeasurementAdjustmentUntilRef = useRef(0)
@@ -1599,15 +1600,6 @@ const VirtualizedWorktreeViewport = React.memo(function VirtualizedWorktreeViewp
   const settings = useAppStore((s) => s.settings)
   const newCardStyle = settings?.experimentalNewWorktreeCardStyle === true
   const reorderRepos = useAppStore((s) => s.reorderRepos)
-  const folderBackedProjectGroupIds = useMemo(
-    () =>
-      new Set(
-        projectGroups
-          .filter((group) => group.createdFrom === 'folder-scan')
-          .map((group) => group.id)
-      ),
-    [projectGroups]
-  )
   const projectGroupByIdForHeaderDrag = useMemo(
     () => new Map(renderedProjectGroupsForHeaderDrag.map((group) => [group.id, group])),
     [renderedProjectGroupsForHeaderDrag]
@@ -4930,10 +4922,10 @@ const VirtualizedWorktreeViewport = React.memo(function VirtualizedWorktreeViewp
               const lineageToggleGroupKey = itemRow.lineageGroupKey
               const experimentalNewWorktreeCardStyle =
                 settings?.experimentalNewWorktreeCardStyle === true
-              const projectGroupId = itemRow.repo?.projectGroupId
               const isFolderBackedRepoChild =
                 groupBy === 'repo' &&
-                Boolean(projectGroupId && folderBackedProjectGroupIds.has(projectGroupId))
+                findProjectGroupForRepo(projectGroupSidebarIndex, itemRow.repo, defaultHostId)
+                  ?.createdFrom === 'folder-scan'
               // Why: experimental in-card lineage inherits the parent surface; legacy cards keep depth-based nested geometry.
               const paddingDepth = nested ? Math.max(0, itemRow.depth - 1) : itemRow.depth
               const getCardContentIndent = (lineageDepth: number): number =>
diff --git a/src/renderer/src/components/sidebar/project-group-header-dom.test.ts b/src/renderer/src/components/sidebar/project-group-header-dom.test.ts
index 3de805ec64d..16ee1d03943 100644
--- a/src/renderer/src/components/sidebar/project-group-header-dom.test.ts
+++ b/src/renderer/src/components/sidebar/project-group-header-dom.test.ts
@@ -12,6 +12,7 @@ import type { FolderWorkspace, ProjectGroup, Repo, Worktree } from '../../../../
 import {
   buildRows,
   buildProjectGroupSidebarIndex,
+  findProjectGroupForRepo,
   findProjectGroupForSidebarOwner,
   getAmbiguousFolderWorkspaceSidebarIds,
   getProjectGroupMutationSelector,
@@ -165,6 +166,22 @@ describe('project-group sidebar identity', () => {
     expect(getProjectGroupSidebarIdentity(local)).not.toBe(getProjectGroupSidebarIdentity(runtime))
   })
 
+  it('keeps folder-backed card geometry scoped to the repo owner', () => {
+    const local = { ...sidebarIdentityGroup('same-id', 'local'), createdFrom: 'manual' as const }
+    const runtime = {
+      ...sidebarIdentityGroup('same-id', 'runtime:env-1'),
+      createdFrom: 'folder-scan' as const
+    }
+    const index = buildProjectGroupSidebarIndex([local, runtime])
+
+    expect(findProjectGroupForRepo(index, ownerHeaderRepo('local-repo', 'local'), 'local')).toBe(
+      local
+    )
+    expect(
+      findProjectGroupForRepo(index, ownerHeaderRepo('runtime-repo', 'runtime:env-1'), 'local')
+    ).toBe(runtime)
+  })
+
   it('carries the exact owner from a rendered header into mutations', () => {
     const runtime = sidebarIdentityGroup('same-id', 'runtime:env-1')