I have been experiencing a problem with the latest Android app for the past month (I suspect the problem has been there since the latest version was released but I only just noticed it recently).
The problem is that any playlists downloaded (set to offline sync), since the upgrade to the latest Android App, don't stay in the Downloaded playlists list between re-launches of the app.
The the tracks in the playlists stay downloaded as if I click the download button again on a downloaded playlist that has disappeared from the Downloade playlists list, it syncs in under a second and moves back to the Downloaded playlists list. The problem is that I have to do this every time that the app is restarted.
Here is a specific playlist that has the problem described here...
That playlist is not published, and I don't want to publish it. Anyway I'm sure you support people are able to access it without me publishing it.
p.s. I have also logged this as a support request via the contact form... Spotify Case # 00326604