Users are able to create errant users in the Windchill database by using the "Email Invitation" field in "Product > Team > Actions > Add Members" (the same issue noted in CS274689). There should at least be checks that confirm the info submitted through the "Email Invitation" field has a proper email address format. Or we should have a supported method for removing the "Email Invitation" field (currently not supported). PTC also provides no supported method for cleaning up these errantly created users. This is a bad design that should be corrected.