It seems that some properties in a batch are not propagated to the group item itself, even if they are the same for all subjobs:
(Publish Comment is an ExtraInfo attribute)
I think the propagating of some columns (extra info/comment are some) was originally left out in 7 due to performance concerns. I’ve already fixed this in 8.0 while I was re-writing all this stuff 
Glorious, cant wait!