Couldn't find a proper place to reply since the official thread for the alert got locked...strangely. So, when a player gets mind controlled, the priority won't go through. No matter what you try it won't heal the tank or a player. Only the group heal will go through. My assumption...its desperately trying to heal the mind controlled person for whatever reason. Looking forward to hearing feedback from other healers.
https://forums.daybreakgames.com/dcuo/index.php?threads/rte3-elite.323032/#post-4511641 Posted here, hopefully Charon sees.