Properly coerce values after GroupConcat.
Properly coerce values after GroupConcat.

learningequality/kolibri,learningequality/kolibri,mrpau/kolibri,mrpau/kolibri,learningequality/kolibri,mrpau/kolibri,indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri,learningequality/kolibri,indirectlylit/kolibri,indirectlylit/kolibri