Update:
Also ponds in HS are set to cancel Flu + Rheumatism debuffs.
Also existence of these skills is settled...they exist in all retail packs. The question is, if they should be used by the monsters.
EDIT: I just want to note, that I have seen such examples of something bugged and forgotten in the past. E.g.: Twins in SoI should give quest items for the quest from which you can get 81 books. It never worked on any chronicle. I stumbled on the bug by accident. The AIs of the 2 RBs had everything regarding the quest inside. Problem was, they were dying in a special way and could not determine last attacker when dying. Adding one line solved the problem.... I consider the HS debuffs as something similar. Everything points to the fact that it should work.