The favorites are handled by the radio service itself. Your dCS device sends a unique identifier with each request and that’s used by airable to associate radio and podcast favorites / history back to you. You’re likely running into an issue where your ID is getting lost in their database which is causing the favorites list to clear and the history to get weird.
The issue that you’re seeing with getting back “Nothing Found” for the automatic lists (local, trending, and region) is likely due to a glitch on their side since those lists are dynamically generated. I would recommend revisiting tomorrow as this could just be a temporary glitch on their end.
We’ve investigated being able to bookmark stations locally so as to avoid issues popping up when the back-end service has a glitch, but there are some technical hurdles to making that happen due to the fact that the radio catalog lives in a state of flux and does change frequently. We don’t have a solution yet, but it’s something that we want to pursue.