Isolating a bug related to frontmost app state

My watchOS app is a tennis scorekeeper where the user, while playing, increments the score after point. Even though I set the shared WKExtension isFrontmostTimeoutExtended property to true in my interface controller's initializer, the app consistently falls out of the frontmost state upon dropping my wrist and raising it again. I'm trying to isolate this issue - is it related to the fact that I also seperately start a Workouts tennis session while playing and testing my app (might there be something I don't know about how frontmost app state works while a Workouts session is in progress?)