Playlist won't stay downloaded for more than a few months

[brainwave0]

I have one playlist that I listen to that usually has about 800 songs in it. I enable the download option for the playlist so I can listen to it offline, but after a month or so I'll find it disabled and none of my songs will be downloaded anymore. This has happened several times. The first time it happened I ended up contacting Spotify support, and I learned that the solution is to go to my Spotify account settings unauthorize all my offline devices. Afterwards, I would have to log back in on my phone and redownload my whole playlist.

Whatever is causing the issue apparently persists across reboots, reinstallations of the app, and even installation on different devices because I've done all those things and it continues to happen.

I suppose the steps to reproduce the issue are:

1. Sign up for Spotify using a Facebook account.
2. Get Spotify Premium.
3. Create a playlist with about 800 songs that includes local tracks.
4. Install the latest version of the official Spotify app (6.2.0.1028) on a smartphone (such as the Samsung Galaxy S4 Mini or the Nexus 6P) running the latest version of Android (6.0.1).
5. Log in.
6. Download the playlist.
7. Listen normally for about 1-3 months.

Can this issue be fixed?