I have been having this problem for about a month now. I am a premium user. Whenever it happens I clean install the app and fromat my sd card. I then reinstall the latest version from google play and resync my playlists. About a week later whenever I am offline, I would launch Spotify on my phone and instead of  the your music page poping up, the login screen comes up. I have changed sync qualityies etc. but I can't seem to find the preoblem. I do have DU battery saver and DU cleaner installed but I need them or my phone will fill up with space very quickly. I also do have Spotify whitelist so the app doesn't clean it.

My phones version is Android 4.4.4

It is not rooted

the spotify version4.3.0.922

I f you have any other questions let me know please 😜