I'm inclined to think it is not a settings issue. It's not an issue with VA, it's an issue with how MB displays Album Artist in the Artist View layout. The album that the Avett Brothers are one of many artists,
Another day, Another Time, and VA is the Album Artist, is first in alphabetical order. When you select any of their other albums, Various Artists is listed as Album Artist when it should be Avett Brothers (and is entered correctly in the tags). Look at another example...
Pharrell Williams, who is a featured performer on a lot of albums in my library. In the first example, Handsome Boy Modeling School is the Album Artist, but it shows as Paul Oakenfold. Second example, Clipse is the Album Artist, but Paul Oakenfold is shown again. Third example, JAY-Z is the Album Artist, but, you guessed it, Paul Oakenfold is shown. If you notice, Paul Oakenfold's album, A Lively Mind, is first in alphabetical order.
Example 1: Handsome Boy Modeling School
Example 2: Clipse
Example 3: JAY-Z
To further my point: The Handsome Boy Modeling School track has Pharrell and Julee Cruise as the featured artists. If you go to Julee Cruise, the Album Artist for that track and that album is Delerium, because, as you can see, their album Chimera is first in alphabetical order.