It seems in Update 23 Doomspheres in the new explorer where given a spell called "chill ray". The spell has a save (I have fort save 98 with no fail on 1) but regardless of the save you take con damage. This is preety ridiculous as doomspheres seem to spam this spell dealing a ton of unavoidable con damage quickly.
This was on a bladeforged btw. And yes according to the combat log the spell "Chill Ray" was causing the con damage. Note= Chill Ray does not exist in player spell book.