I try doing a rescan every time this happens, but it only seems to reset if I delete the app and reinstall. I haven't moved or done any major rearranging. I do also check the number of files has changed when I do rescan. It will say about 35,000 files, but when it goes all wanky, it wont even play any where near the amount of files it says it has in the library.
I did change phones recently. Could that be the issue? I've never had any issues when changing phones before.