Offline Playlists not staying downloaded

[KB841]

So I have spotify premium. I've had it a long time on my android mobile but recently I installed it on my android car stereo.
My playlists sync up onto the car stereo no problem, I download them and they play offline.
But when the stereo is tuned off and started back up the playlists are not downloaded and it needs an internet connection to quickly re-download the playlists again. This happens every time. I do not have this issue with my mobile.
Can anyone advise me as to how this can be resolved.

Thanks in advance