diff --git a/frontend/src/lib/shared/discussion/MentionDropdown.svelte.test.ts b/frontend/src/lib/shared/discussion/MentionDropdown.svelte.test.ts
index 95124728..0499cf7b 100644
--- a/frontend/src/lib/shared/discussion/MentionDropdown.svelte.test.ts
+++ b/frontend/src/lib/shared/discussion/MentionDropdown.svelte.test.ts
@@ -258,8 +258,19 @@ describe('MentionDropdown — search input', () => {
 // same export so a regression in highlightedIndex/selection logic is caught
 // at the unit level. The full E2E focus-chain test is deferred to a separate
 // issue (Playwright).
+//
+// These unit tests directly invoke the exported `onKeyDown` to pin its
+// behaviour in isolation. They do NOT exercise the Tiptap forwarding
+// chain (PersonMentionEditor.suggestion.render() returning { onKeyDown })
+// — that integration is covered by the 'ArrowDown moves the highlight'
+// test in PersonMentionEditor.svelte.spec.ts. Sara on PR #629 round 3.
 
 describe('MentionDropdown — onKeyDown forwarding', () => {
+	// flushSync ensures Svelte reactivity propagation completes before
+	// asserting (uniform across all four key tests so the next reader
+	// doesn't have to figure out why some are wrapped and others aren't).
+	// Felix #1 suggestion on PR #629 round 3.
+
 	it('ArrowDown advances aria-selected to the next option in the listbox', async () => {
 		const container = document.createElement('div');
 		document.body.appendChild(container);
@@ -338,7 +349,10 @@ describe('MentionDropdown — onKeyDown forwarding', () => {
 		try {
 			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
 
-			const consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Enter' }));
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Enter' }));
+			});
 			expect(consumed).toBe(true);
 			expect(command).toHaveBeenCalledTimes(1);
 			expect(command.mock.calls[0][0].id).toBe('p1');
@@ -359,7 +373,10 @@ describe('MentionDropdown — onKeyDown forwarding', () => {
 		});
 		try {
 			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
-			const consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Escape' }));
+			let consumed = true;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Escape' }));
+			});
 			expect(consumed).toBe(false);
 		} finally {
 			unmount(instance);