Found 2 problems:
assembly hs1: subtrack "badGroupsBadChild" has 'group _MISSINGFROMGROUPSPEC' but its parent "badGroupsComposite" has 'group _test'. Subtracks inherit their parent's group. Either remove the 'group' line from the subtrack, or set both parent and subtrack to the same group.
warning: missing hub overview description page. Add a 'descriptionUrl hubDescription.html' line to hub.txt.
