I kept crashing every time I joined a server. Finally I removed Light Overlay and Cloth-Config-Forge, and I was able to join without a problem. The crash log is here:

https://paste.ee/p/8WC8O

I was using Light Overlay successfully on this server for a while. Shortly after going to the nether (a minute or two), I crashed. I kept crashing every time I tried to rejoin.

The server did not have Light Overlay or Cloth Config. Since they are both client-side mods, I don't assume this would matter, but I thought I'd mention it anyway.

This bug may sound similar to #60, but when you look at the crash logs, they occur in different places. That's why I decided to make a new bug instead of adding to that one.

I had this same issue happen again without Light Overlay. So, it seems that I was wrong to assume that it was due to Light Overlay. I've closed the issue now.