diff --git a/packages/test-utils/src/realtime-helpers.ts b/packages/test-utils/src/realtime-helpers.ts
index fe4b1da..f470f00 100644
--- a/packages/test-utils/src/realtime-helpers.ts
+++ b/packages/test-utils/src/realtime-helpers.ts
@@ -73,7 +73,10 @@ export async function subscribePostgresChanges<T = Record<string, unknown>>(
 
 	function waitFor(
 		predicate: (e: { eventType: string; new: T; old: T | null }) => boolean,
-		timeoutMs = 5_000
+		// 10s default: under load (full `just test-all`), the Phoenix socket can take
+		// a beat to propagate a fresh subscription's filter before the mutation fires.
+		// Passing runs resolve immediately on event arrival — this only bounds the flake.
+		timeoutMs = 10_000
 	) {
 		const existing = events.find(predicate);
 		if (existing) return Promise.resolve(existing);