Describe the bug
The game crashes when it starts.
1.16.3 crash report (with other mods)
https://paste.ubuntu.com/p/Z5pdTJvMSf/
1.16.2 crash report (just Mubble, Dawn API, and Fabric API)
https://paste.ubuntu.com/p/Rm3gQzfSPV/

To Reproduce
Steps to reproduce the behavior:

1. Install Mubble 4.0-pre3 on Minecraft 1.16.2 or 1.16.3
2. Start the game

Expected behavior
The game starts without crashing.

Thanks for the report!

This bug has been fixed for the next version.