diff --git a/frontend/src/routes/SearchFilterBar.svelte.spec.ts b/frontend/src/routes/SearchFilterBar.svelte.spec.ts
index 446cd046..723e5858 100644
--- a/frontend/src/routes/SearchFilterBar.svelte.spec.ts
+++ b/frontend/src/routes/SearchFilterBar.svelte.spec.ts
@@ -132,6 +132,9 @@ describe('SearchFilterBar – undated-only toggle (#668)', () => {
 	async function openAdvanced() {
 		const filterBtn = page.getByRole('button', { name: 'Filter', exact: true });
 		await filterBtn.click();
+		// Wait for slide transition to finish before interacting with contents —
+		// clicking during the transition triggers track_reactivity_loss in Svelte 5 async.js
+		await expect.element(page.getByTestId('undated-only-toggle')).toBeVisible();
 	}
 
 	it('renders the "Nur undatierte" toggle in the advanced row', async () => {