Hello, people! I wish to check my discovery. Look, we (madness sorcs) have a skill "Death field".
*Creates a death field at the target location, dealing 2240 - 2600 internal damage and healing you for 1% of maximum health for each target struck. Strikes up to 5 targets within an 8-meter radius.*
It is also affected by "Devour" talent, so we can get 2% of max HP for each target, up to 10% of max HP.
In fact, Death field healing is the same thing with the "crit DOT proc", regardless of affected targets number.
Please, try checking it by yourself and, if I correct, we need to write a bugreport.