Sandbox: https://codesandbox.io/s/cranky-kapitsa-op3jh

Repro: type "a" and then after a second "b"

Expected: Eventually you'll see "ab" in all fields. Pending "..." indicator goes away.

Actual: You'll keep seeing "a" in low pri field. Pending "..." indicator is stuck.
update.expirationTime = renderExpirationTime;
    currentlyRenderingFiber.expirationTime = renderExpirationTime;
  } else {
    if (
      fiber.expirationTime === NoWork &&
      (alternate === null || alternate.expirationTime === NoWork)
    ) {
      
      
      
      const lastRenderedReducer = queue.lastRenderedReducer;
      if (lastRenderedReducer !== null) {
        let prevDispatcher;
        if (__DEV__) {
          prevDispatcher = ReactCurrentDispatcher.current;
          ReactCurrentDispatcher.current = InvalidNestedHooksDispatcherOnUpdateInDEV;
        }
        try {
          const currentState: S = (queue.lastRenderedState: any);
          const eagerState = lastRenderedReducer(currentState, action);
          
          
          
          
          update.eagerReducer = lastRenderedReducer;
          update.eagerState = eagerState;
          if (is(eagerState, currentState)) {