On the Partner Greenline for QDC in Module 3 we're preparing two entities for publishing. The primary index contact.cont_id is actually a string, needs to be converted TO_INTEGER.
There's a learning point for all of us, too: Simply correcting that in the prepare-workflow does not do it. You have to delete and re-insert most subsequent steps. Something for a next release, I think. For now: Validate early, validate often.