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.
const [A, _updateA] = useState(0);
        const [B, _updateB] = useState(0);
        updateA = _updateA;
        updateB = _updateB;
        let C;
        if (props.loadC) {
          const [_C, _updateC] = useState(0);
          C = _C;
          updateC = _updateC;
        } else {
          C = '[not loaded]';
        }
        return <Text text={`A: ${A}, B: ${B}, C: ${C}`} />;
      }
      ReactNoop.render(<App loadC={true} />);
      expect(Scheduler).toFlushAndYield(['A: 0, B: 0, C: 0']);
      expect(ReactNoop.getChildren()).toEqual([span('A: 0, B: 0, C: 0')]);
      act(() => {
        updateA(2);
        updateB(3);
        updateC(4);
      });
      expect(Scheduler).toHaveYielded(['A: 2, B: 3, C: 4']);
      expect(ReactNoop.getChildren()).toEqual([span('A: 2, B: 3, C: 4')]);
      ReactNoop.render(<App loadC={false} />);
      expect(Scheduler).toFlushAndThrow(