Album Artist not displaying multiple artists

If I have multiple artists under the Artist field, in the track listing I see, for example, "Sir Charles Mackerras\Scottish Chamber Orchestra" (using the "//" delimiter"). But when I enter the same text under Album Artist, I see only "Sir Charles Mackerras" in the track listing.

However, if I actually view the tags in something like foobar2000 I see the Album Artist tag as expected: "Sir Charles Mackerras; Scottish Chamber Orchestra" (where the delimiter has been replaced by a "proper" text separator).

I would have expected multiple artists to be displayed in the same way under both the Artist and Album Artist fields. Is there a reason for this difference?

Could be.
It depends on how you defined "Value" for the column.
If you want to see that column as a multi-value field, then try
Value: $meta_sep(albumartist,\\)
Please note that while a number of players can deal with several artsts and genres, they often refuse to recognize more than one field of the type ALBUMARTIST, TITLE and ALBUM.

How to define a column, see the documentation: