Starting this in the Dev forum so we can resolve the issue.
I finally traced through my logs and got a line where it happens, not sure if this is all the cases where it does, just one of them.

Code:
WARNING: OP_CorpseLocResponse (00d3) (dataLen:516 != sizeof(corpseLocStruct):16)! SPELL: 
<Player name removed> has begun casting 'Corporeal Empathy' 
- Casting time is 2.5 Seconds 
WARNING: OP_CorpseLocResponse (00d3) (dataLen:516 != sizeof(corpseLocStruct):16)!