AR18PRIE.CRE Assertion Failed, seems to be an animation problem

AR18PRIE.cre, the priest you encounted in the North Forest region, is throwing up an Assertion Failed error, more specifically "Assertion Failed! Return Address: 0x84C3C1 File: Obj.Animation.cpp Line: 20514 Expression: !<m_weaponCode&MELEE_1HLR_MASK> Message: <null>" when hit, or when casting certain spells. Seems like his animation is corrupted somehow, I've tried Ctrl+Y and that works fine, and if I change him into something non-humanoid the problem stops (turned him into a basilisk for fun, hehe)

Anyone know if it's possible to quickly fix this without changing his actual animation? As hilarious as fighting the basilisk priest is, (or the squirrel priest, or the moose priest, or any other variations thereof.....) it would be nice to just have a regular old human as intended.

Well, I tried swapping out the backup for this creature from the Stratagems backup folder, but that did not work. Then I tried making a whole bunch of different tweaks to the CRE file, one at a time in Near Infinity, before finally figuring out what the (rather obvious, in hindsight) problem with this creature was. He was set to have a Mace +1 in his shield slot, and a regular Mace in his mainhand. HOWEVER, the creator of this .CRE file also gave this priest a sling in his 2nd hand. When the script calls for the priest to switch to a ranged weapon, the game is unable to do so because the offhand is in use. Of course, freeing his offhand or removing his sling altogether completely fixes this problem.