For the last few versions now - I can't recall exactly when it happened- but I've noticed what I can only call a bug.
Any time Spotify is closed out of memory in Offline mode it clears your playlists (even synced songs/lists) and you are REQUIRED to go back online to download your playlists before you can listen to anything.
When you sync songs to your device the intent is to play them where you have no or bad connection...
Steps to reproduce:
1. Tap a song 2. Tap the Download slider 3. Wait for it to finish syncing 4. Switch to Offline mode 5. Listen until done... 6. Clear the app from phone recent apps with offline still on 7. Re Open the app...to only be annoyed by having to go back online...again...even though your license still has 20+ days on it.
Normally, I'm doing this where I have WIFI so it's a non issue, but still very annoying. Even though I have the songs synced to my device I still find it uses a significant amount of data so I prefer it to be in offline mode. For months this was not a problem, but recently it has become a problem and very annoying
My Device: ASUS ZenFone 2 Z00A (ZE551ML) Operating System: Happens on stock Android 5.0 software AND CyanogenMod 13 (Android 6) Free Storage: 30GB
Additional info/troubleshooting: I know it's not my device since I was able to reproduce this situation on a Samsung S5 Neo (phone is less than a week old and Spotify was JUST installed 2 days ago).
Triple checked my storage, used the clear all data except the app option from within the app. Based on the test with a freshly installed and completely separate Spotify account, i don't feel I need to reinstall the app. If this is by design...it's a flawed design, what if I was going away for a week and to avoid annoying lag on my device I close all my apps, with no internet I wouldn't be able to re sync my playlists.
When you launch spotify offline, it opens on the home page which displays that message as it can't display any of the usual content. However, if you go to Your Music from the menu bars or by swiping to the right, you should find that your downloaded music is available and playable as usual.