Album art doesn't change
Yeah, album art caching sucks.. I know exactly what you're going through. But I'm pretty sure I have a working solution for turning off auto-relation.

You may or may not need root, depending on if your album cache is stored on /sdcard/Android (which usually is the case) or in /data/data.

Go into /sdcard/Android/data/com.android.providers.media/albumthumbs -- where all the album arts are stored, and delete all of them.

But that isn't going to fix the problem for future offenders. To do that, we'll have to disable caching. I got the idea from a guy on an XDA thread.

To effectively disabling caching, thus turning off auto-relation, change the permissions on the albumthumbs folder to read-only on all groups. If the folder is part of the app data under /data/data it may be difficult to do so, even with root. On Samsung and ZenFone, you won't run into this issue.

Hope this helps!