Apple Music Cover Art Synchronisation (iTunes 12.2)

All of my music has just finished synchronising with my iCloud Music Library, and all the tracks have uploaded fine.

However, I have 2 albums that haven't synchronised their cover art and the compilation albums that I have all had a random cover selected for them. All of them have the correct artwork in my iTunes, but it's not syncing across other devices.

I've changed a few details on one of the albums' tracklist and the changes are almost instant across devices, but clearing and using 'Get Album Artwork' repeatedly does nothing across other devices.. It's one of those things that's just really annoying when trying to archive your music properly.

Is there a way to force an update of the artwork?

Currently using iTunes 12.2 on a late 2013 MBP (OS X 10.10.4) and iPhone 5s/iPad Mini 1 freshly updated to 8.4.