2017 and it's still happening to me regularly. I'm on a Galaxy S7 edge. Stock, never fiddled with anything in it. Especially annoying since I bought the app specifically so I could listen to music when I'm NOT online. On long drives, flights etc. I'm in a country with poor wifi infrastructure and I only use data rarely, which means I only connect through my home wifi exactly when I DON'T need Poweramp to listen to music.
It stops playing around an hour or two after losing connection. Then insists I don't have a license. I've been forced to install other (free) music players as backups because I never know when Poweramp decides to eff my day up. Sure it starts up fine once I get home and connect or find a connection, but the main point why I bought the app is so I could USE IT WHEN I'M OFFLINE. Jeez.
Is there seriously still no action taken on this issue? That page where it says "no internet connection is needed" is pretty much a lie at this point. It doesn't help at all when the solution to fix the issue is to "find a connection." How exactly does that translate to "no internet" when you need internet to fix an issue that happens ONLY when there's no internet? An issue that renders the app just a pretty wallpaper.