Thanks. I noted the problem some days after the tags were changed. I used Picard just once, AFTER going into settings to make Picard prefer album tags over live tags over remix tags etc.
ITM I cannot provide a screenshot, but I'll post one after it finishes a new cycle of tagging, which I'm currently doing after resetting preferences.
EDIT: I tried googling, uninstalling, reinstalling, using AppCleaner... I can't find a way to completely reset Picard's prefs (v 1.3.2, OSX Yosemite), so I sticked to resetting only the release prefs.