Using revealOrder="backwards" in SuspenseList only works for very short wait times

I realize that this is still experimental, but I figured it would still be good to report bugs. If not, feel free to close this issue.

I was playing around with the examples in https://reactjs.org/docs/concurrent-mode-patterns.html#suspenselist and noticed that revealOrder="backwards" didn't seem to work. The trivia items never appear before the posts. After fiddling around with the example in https://codesandbox.io/s/black-wind-byilt i noticed that it works if the timeout is set around 500 ms or below for the trivia items. But if you set it to for example 1000 ms, it will instead wait until both trivia and posts are available.

revealOrder="forwards" seems to work regardless of how long the timeout is.

I tried changing React version to the latest experimental version (0.0.0-experimental-c76e4dbbc-20210722), but it did not seem to make a difference.

Reproduza o exemplo de SuspenseList da documentação do React e do CodeSandbox vinculado, comparando revealOrder="backwards" com atrasos de trivia de 500 ms e 1000 ms. Comece verificando a versão experimental do React informada e o comportamento do timeout do exemplo; considera-se concluído quando a causa for identificada e o comportamento da ordem backwards para esperas mais longas for corrigido ou claramente abordado.