Reproduction showcasing that useId() doesn't work inside <Suspense>.

git clone git@github.com:brillout/react-bug-useId-suspense
cd react-bug-useId-suspense/
pnpm install
pnpm run dev

As single line:

git clone git@github.com:brillout/react-bug-useId-suspense && cd react-bug-useId-suspense/ && pnpm install && pnpm run dev

Go to http://localhost:3000 and observe the following:

1. The text I'm lazy loaded... never resolves to Hello, which is unexpected.
2. The console.log() logging id: :r0:, then id: :r1:, then id: :r2:, etc. In other words: the ID provided by useId() is not stable, which is unexpected. This is the root cause of why 1. doesn't work as expected.

The following commits confirms that the root problem is indeed useId() not returning a stable ID when used inside <Suspense>.

• 359df7 which replaces const id = useId() with const id = 'some-static-id', then 1. works as expected.
• ba224b replaces <Suspense> with useState() to showcase that useId() then works as expected (i.e. returns a stable ID). This indicates that the problem is indeed caused by using useId() inside <Suspense>.