Did you find out anything?

Have you found a solution?

You ever found a solution? Whole isCompanionAppInstalled Apple Watch stuff seems so buggy.

Is there more information to this topic, for example in the docs? Does the iPhone app really wake up, and in what "state" does it wake up? Is it some kind of background state, or does it appear as the new active iPhone app? In my testing, the app did not wake up, and I have no idea where to look for solutions.