Server crash when some Ars Nouveau interactions involve some Alex's Mobs mobs.

Crash Report: https://gist.github.com/MattB70/52c995fb4b15df3bc5db2615397f859d

Let me know if I should cross report this on Alex's Mobs repo if the issue doesn't appear to be solvable on this end. The was reported by a player on my server.

This doesnt really seem fixable on our end, multipart entities are being marked as living entities. It is on them to correctly handle bad states. Vanilla provides a multi-part class to help compatibility.