Client Log
https://mclo.gs/4WBIT3v
Server Log
https://mclo.gs/8YIcSjG

Client Crashes and Modmenu appears to take the fall

This is a dirty mixin issue which has been fixed. I posted a patched har on the discord if you can't wait for the 0.10.9 1.19.4 port later this week.

For reference: https://discordapp.com/channels/981828752029925408/981828752659083266/1105495479552327700

Duplicate of #584, fixed by #585

New version is up now.