https://pastebin.com/C7S9wKXf

I'm running 1.12.2-1.1.0-9 , Whenever the player on my server attempts to walk through an active portal, with an active end elsewhere, whether in the same loaded chunks or another dimension, it causes the crash detailed above ^ , crashes the server and the client. The client is able to relog afterwards, and the issue is apparently only when moving through the portal, not after the placement of the block/assembly of the portal itself or powering of it.