Groups should respect OG groups that are taxonomy term entities instead of nodes

I have a few OG groups that are taxonomy terms - I was writing a migration script to migrate some nodes from a D6 install to a D7 one, Everything was going swell until I tried to set the audience of the migrated nodes. I got an error, something along the lines of:

WD node: MigrateException: array_values() expects parameter 1 to be array, null given                                                              [error]
File /Users/chris/Sites/grammypro/docroot/profiles/commons/modules/contrib/commons_groups/commons_groups.module, line 759 in
MigrationBase->errorHandler() (line 530 of /Users/chris/Sites/grammypro/docroot/sites/all/modules/contrib/migrate/includes/base.inc).
array_values() expects parameter 1 to be array, null given                                                                                         [error]
File /Users/chris/Sites/grammypro/docroot/profiles/commons/modules/contrib/commons_groups/commons_groups.module, line 759

I checked out the code in question and saw that it was because the node that I was migrating, its author, had not contributed to this group before, and so the commons_groups_first_contribution() method was called. That method only cares about groups that are just nodes. I'm using taxonomy terms as the entities for some groups (in addition to node-groups).