The Playmode tests are probably using the GameTime to decide when to timeout, which make most tests that would touch Time.timeScale timeout way faster than expected.

Here's a snippet that reproduces the problem:

public class Wrapper
{
[UnityTest]
public IEnumerator ShouldNotTimeoutButItDoes()
{
Time.timeScale = 10;
yield return new WaitForSecondsRealtime(3.1f);
Assert.IsTrue(true);
}
}