I have a log from when it happened, but I had discovered a bug with another mod, then turned around, was killed, and saw a fatal server error before my client crashed to desktop. The log is here

you should include that log

I still have no idea what could possibly be causing this crash. I also haven't seen a crash log for this issue where random patches isn't installed.

If I had to guess what was going on here:

It looks like the client connection is destroyed but the client tick event is still being called, and trying to send the packet. I'm going to try to put in a sanity check for this and see if this stops happening.

ok i see what you did there.