https://codesandbox.io/s/upbeat-frost-3tt25

1. Press Suspend, see "Loading..."
2. Wait five seconds, you'll see "Happy birthday" at some point 
3. You won't see it again no matter how long you wait

Expected: you'll see it every five seconds.
if (current === null) {
     
     
    if (nextProps.fallback !== undefined) {
      tryToClaimNextHydratableInstance(workInProgress);
       
      if (enableSuspenseServerRenderer) {
        const suspenseState: null | SuspenseState =
          workInProgress.memoizedState;
        if (suspenseState !== null) {
          const dehydrated = suspenseState.dehydrated;
          if (dehydrated !== null) {
            return mountDehydratedSuspenseComponent(
              workInProgress,
              dehydrated,
              renderExpirationTime,
            );