diff --git a/tests/browser/workspace-library-editor.spec.mjs b/tests/browser/workspace-library-editor.spec.mjs
index 2a17b3e3..725b5427 100644
--- a/tests/browser/workspace-library-editor.spec.mjs
+++ b/tests/browser/workspace-library-editor.spec.mjs
@@ -635,7 +635,11 @@ test('restored storage after a confirmed save or before an archive offers an exp
         const response=await route.fetch();await expect(await restore()).toBeOK();return route.fulfill({response});
     });
     await page.getByRole('button',{name:'Edit metadata',exact:true}).click();let dialog=editorDialog(page);await ready(dialog);
-    await field(dialog,'Notes').fill('Lost to a restore');await button(dialog,'Save').click();
+    await field(dialog,'Notes').fill('Lost to a restore');
+    // The save's answer waits for a whole restore in the route above; wait for that answer, not the 5 s expect
+    // default (#501 merge queue: under load the restore outlasted it on WebKit).
+    const saved=page.waitForResponse(item=>item.request().method()==='PATCH'&&new URL(item.url()).pathname===`/prompt_manager/library/${f.positive_id}`);
+    await button(dialog,'Save').click();await saved;
     await expect(note(dialog)).toHaveText('Saved; Library refresh failed because prompt storage was restored. Reload the Library to see current data.');
     expect(await actionNames(dialog)).toEqual(['Reload Library','Create text revision','Archive…','Cancel','Save']);
     for(const name of ['Create text revision','Archive…'])await expect(button(dialog,name)).toBeDisabled();
diff --git a/tests/browser/workspace-system-diagnostics.spec.mjs b/tests/browser/workspace-system-diagnostics.spec.mjs
index 9f811362..2f4cc07a 100644
--- a/tests/browser/workspace-system-diagnostics.spec.mjs
+++ b/tests/browser/workspace-system-diagnostics.spec.mjs
@@ -274,11 +274,18 @@ test('level filter is minimum-level over all six choices', async ({ page, reques
     for (const line of (await lines(page).textContent()).split('\n')) expect(line).toMatch(/^\d\d:\d\d:\d\d [A-Z]+ +\S/);
     expect(urls.at(-1)).toBe('?limit=100');
     for (const minimum of LEVELS) {
+        // Wait for this level's answer: the previous level's lines also hold the CRITICAL line, so seeing it proved
+        // nothing, and under load the filtered answer painted after the check (#501 merge queue, firefox).
+        const answered = page.waitForResponse(item => new URL(item.url()).pathname === LOGS_URL
+            && new URL(item.url()).search === `?limit=100&level=${minimum}`);
         await level.selectOption(minimum);
+        await answered;
         await expect.poll(() => urls.at(-1)).toBe(`?limit=100&level=${minimum}`);
         await expect(lines(page)).toContainText('CRITICAL The database could not be opened');
-        const shown = await shownLevels(page);
-        expect(shown.every(name => LEVELS.indexOf(name) >= LEVELS.indexOf(minimum)), `${minimum}: ${shown}`).toBe(true);
+        await expect.poll(async () => {
+            const shown = await shownLevels(page);
+            return shown.every(name => LEVELS.indexOf(name) >= LEVELS.indexOf(minimum)) || `${minimum}: ${shown}`;
+        }).toBe(true);
         if (minimum === 'DEBUG') await expect(lines(page)).toContainText('DEBUG Thumbnail cache lookup');
         if (minimum === 'WARNING') {
             await expect(lines(page)).not.toContainText('Database backup verified');