Using default settings for the expanded panel, an album that has all the tracks by the album artist except 1 (track 16 in this case), will display like this:
But as soon as you add a second tag field to display, the artist gets replicated for each and every track:
I think also in this case only the differencing artist should be displayed.
But to make things even better, personally I would prefer it if any auto-populating would be completely disabled as soon as you customise the expanded panel by adding other fields.
Virtual tags give plenty opportunities to customise that panel without the need for MB doing auto-generating.
(I know related matters have been discussed before, and perhaps there are some solutions for this already, but I haven't been able to find these topics)edit:
Hm, I found a way that seems to solve this. When using a virtual tag <Title¨>, instead of the regular Title tag for the first field, things seem to behave as I desired.
But this will cost an extra virtual tag which could be problematic for some users.