@kugiigi And it's not specific to CRUST. Ubuntu Phone devs wanted all apps to be SIGSTOP'ed except when the screen was on and the app focused. And then background downloads, music playing, messaging, .... All sorts of exceptions cropped up.
Google's latest Android is ferociously aggressive in not running apps (even when selected for no "battery optimization"). Resulting in people not getting messages until their friends have long gone to lunch together without them.
So CRUST is just an outlying data point of what can happen when battery optimizations are pursued without a context of usability.
And thank you to the devs for responding so quickly! I'm glad this issue is on your radar screen.