This doesn't happen with every client, only one player on our dedicated server.

He could not find the crash log, here is a paste of his console with the crash log at the end.

https://gist.githubusercontent.com/digghair/c5b13132386157feb38f059015d8d1df/raw/61bd873b2bf0c918faacb932d06dd3ddc1e5a38d/gistfile1.txt

Modpack- TownCraft TWO test
CFB- CookingForBlockheads_1.16.3-9.2.1
Forge -34.1.9

Reproduced here with a different player-

Crash log- https://gist.github.com/ProsperCraft/0f1caf93d67c51148870702d12033f97
Client log- https://gist.github.com/ProsperCraft/f95628ce4f3265f4e804779e55652533

Forge .16

yes, this is the issue we have, some people crash, some don't.

One of my server members is having the same problem, but we are unaffected with exactly the same mods:

Crash log - https://gist.github.com/egguchan/efbc62c880c057e1cb3305e2a90731a1