These are deleted groups. When a group is deleted from Windchill, most of the DB entries related to the group are deleted. However, Windchill keeps the entry in the WTGroup table, but makes two modifications to it. First, the name of the group is updated to be '{wt.org.WTGroup:<idA2A2>}<Name>'. Then, the value of the 'disabled' column is set to 1. The same is also done when users and orgs are deleted.
Whenever Windchill does any query for users/groups/orgs, the query always includes the predicate 'disabled=0', so that only valid groups are returned. If you want your code to ignore these groups, then you should modify it to only query for groups with a value of 0 in the disabled column.