Editing album artists

How album artists should be edited and are displayed has changed.
I would like an explanation of the rules, if anybody has answers.
It used to be that primary artists were displayed separated by slashes, and if the album artist string came separated by commas, for example, you got a mess.
In 1.8 the primary artists are displayed with commas (which looks much more human and less computerize, thanks) but when the album artist string is separated by commas I still get a mess:

The upper line is the album artist, the lower one is the list of primary artists. Obviously the system couldn’t recognize the comma-separated album artist string as matching the set of primary artist.
This from the Edit dialog: