Local files' album art not showing up on Android/iOS (randomly)

[clicheusername]

On iOS, it seems to have album art for some local files. But on Android, it's pretty much non-existent.

I was able to fix the issue on my computer by removing all special characters (hyphens, parentheses, underscores) from the filenames and restarting Spotify. 

But the Android app still has issues displaying it. Just shows the blank grey disc icon. Any ideas on how to force album art to be displayed?

I've tried redownloading my playlist and readding. Reinstalled my app but every phone I've tried has had this issue, no matter the Android version or app version.  I don't know what else I can do. 

[clicheusername]

Somehow fixed it. Re-DLed and left the Spotify app open for about an hour (after I fixed the album art issue on desktop) and then restarted (force closed) the app and now local file album art shows up.