I've tried rescanning files multiple times, changing things here and there, and can't seem to find where my stuff is messed up. I think the problem is in MusicBee, because it looks like the tag picardtitlefull is assigned correctly. This first screenshot shows what I mean:
As you can see, in the Tags (2) tab, the "picard title full:" field is empty, but in the Tag Inspector, PICARD TITLE FULL......TXXX/picardtitlefull is there and set to the right thing.
Perhaps I set up the custom tag wrong. Here's what that looks like:
So, my plaintive cry is "What am I doing wrong?"