My experience with Android 8.0 is that when you install an app, it gets permission to run in the background by default. But I like to kill everything running in the background that I don’t absolutely need, including the ReSound Smart 3D app if I don’t plan to change my HA settings. I can still check HA settings and change them, check rechargeable battery status by launching the app, running it in the foreground briefly, then quit.
Today for the first time, I had a problem with the Phone Clip+ disconnecting regularly with great frequency. When I looked, I hadn’t switched back to allowing the Smart 3D app to run in the background and I’d also gone a very long time running the Smart 3D app off and on without powering off my phone. So the first thing I did was rebooted my phone and after that for the remaining 20 minutes of a walk the streaming connection was solid. In the future, I’ll look into whether not allowing the 3D app to run in the background is a potential cause of lost connections while streaming (I don’t allow my podcast players to run in the background and that doesn’t seem to affect streaming).
So based on my very limited experience one thing might be whether the user periodically reboots their phone at all (I power mine off and on at least once a day). And the other might be if they’re like me and messing around with what apps can run in the background - that might have had some influence on my connectivity problems today and perhaps theirs?