Spotify logged me out after an update, I couldn't log back in due to being in offline mode , sound familiar ???
The only way to avoid this issue altogether is to avoid using offline mode fullstop.
Download a firewall for your device and block spotify instead of selecting offline mode.
When you want spotify to connect then unblock in firewall or turn firewall off.
Even better define rules for how you want spotify to access the internet ,
You can still listen to your downloaded playlists , albums & tracks , you don't need to use offline mode
My firewall settings for Spotify on my android : Mobile data / Wifi
When i'm at home i'm on my wifi network , that's where i use spotify the most and will download .
When i'm not at home i connect to mobile data network , spotify will be blocked but i can still listen to all my downloads , nothing else is blocked , just spotify.
Never do i put Spotify in offline mode , i just force it offline.