For a while I have been struggling with an issue where songs previously downloaded for offline availability show up as NOT downloaded for no apparent reason. I haven't discovered a distinct pattern yet, though I seem to notice it happening more often just after I turn on my device.
The 'Download'-toggle is turned off on playlists and albums where it should be on, turning it on again just downloads all the songs again. Spotify is still reported to use over 10GB of storage though, so it doesn't seem like the cached files themselves got deleted.
This happens every one or two weeks, though right now it is even more annoying since I left for a trip a week ago and will be without a WiFi connection for a while. I would like to know what's causing this and how to prevent it from happening, because having to redownload your entire library every two weeks is just a pain.
Premium (part of a family plan)
Moto G5 Plus
Android 7.0 Nougat
188.8.131.520 (though i've had the issue through many versions before)
While Android reports Spotify using 10GB+ of storage, no used storage is shown Spotify settings. The download quality setting has also reverted from 'Very High' back to 'Normal'