diff --git a/internal/check-shared-component-reached-bundles.mjs b/internal/check-shared-component-reached-bundles.mjs
index 178870cca..afa5c211b 100644
--- a/internal/check-shared-component-reached-bundles.mjs
+++ b/internal/check-shared-component-reached-bundles.mjs
@@ -63,12 +63,15 @@ const MARKERS = [
     // The built shape keeps its structure through minification even though names change:
     //   unguarded  const o=e.getRootNode();if(!(o instanceof ShadowRoot))
     //   guarded    if(!e)return;const o=e.getRootNode();if(!(o instanceof ShadowRoot))
-    // The `instanceof ShadowRoot` tail pins it to ensureEngineCSS: useShadowStyles has its own
-    // (older) `if(!a)return;…getRootNode()` guard, which must not count.
+    // The `instanceof ShadowRoot))return` tail pins it to ensureEngineCSS: useShadowStyles has its
+    // own `if(!n)return;const i=n.getRootNode();if(!(i instanceof ShadowRoot)||…` — which matched the
+    // first version of this regex and would have counted a rebuilt bundle as fixed WITHOUT the guard.
+    // The trailing `)return` is ensureEngineCSS's early exit; useShadowStyles continues with `||`.
+    // Proven both ways on a rebuilt doxa-simple-map: guarded source matches, guard stripped does not.
     id: 'map-unmount-guard',
     component: 'library/composables/useMapInstance.js',
     sourceRe: /if \(!element\) return\n\s*const root = element\.getRootNode\(\)/,
-    builtRe: /if\(!([\w$]+)\)return;const ([\w$]+)=\1\.getRootNode\(\);if\(!\(\2 instanceof ShadowRoot\)\)/,
+    builtRe: /if\(!([\w$]+)\)return;const ([\w$]+)=\1\.getRootNode\(\);if\(!\(\2 instanceof ShadowRoot\)\)return/,
     marker: 'if (!element) return (ensureEngineCSS)',
     landed: 'studio, 2026-09-25',
     why: 'a map whose pane unmounts mid-initialise no longer throws "reading getRootNode" (check-map-unmount-mid-init)',