This is a very specific setup - if a pack does not have a levels.nxmi file for its base folder, but has an author listed in the info.nxmi file, the author field will not work. The version field still does.
It's fine if the subgroups (ranks) don't have a levels.nxmi file, and conversely, it does not avoid this bug if they do have one. All that matters is the base pack.
Fixed in commit b67df2a.