Spells: Mobs CHing From Unknown Spell

[Socratic]

Seen it 3 times today so far. Once in Seb while killing a reaver, twice trying to kill Overking in Chardok.

These seem to be the relevant lines:

Chardok Overking:
[Sun May 04 20:29:16 2014] Overking Bathezid begins to cast a spell.
[Sun May 04 20:29:26 2014] Overking Bathezid regains concentration and continues casting.
[Sun May 04 20:29:26 2014] Overking Bathezid is the victim of an unknown spell.
(my logs did not catch the 2nd CH he did during this fight)

Sebilis Myconid Reaver:
[Sun May 04 16:56:45 2014] myconid priest begins to cast a spell.
[Sun May 04 16:56:55 2014] Myconid reaver is the victim of an unknown spell.

In all of these cases the "unknown spell" resulted in the effected mob instantly returning to 100% health. Also in both of these cases the resulting HP gain was far far more than a traditional CH (Overking for example went from 40% to 100% twice in the same fight).

Thanks for reading.