State That Didn't Survive Navigation

Component-local state in a layout that remounts is not guaranteed to survive navigation; true persistence requires a context provider in the root layout, URL search params, or an external store living outside the React tree

Adding "use client" to layout.tsx guarantees state will never reset on navigation

useState always persists across navigation in the App Router by default, so the reset indicates a bug in Next.js

Wrapping the layout in Suspense prevents the remount that causes state loss