The watersource-1.3.60-release-1.18.1 has some problem in the Datapack that is causing problems when loading.

https://crashy.net/ZYYFR1IEcNxIz4pTTq4P

I have the same issue
https://gist.github.com/WelpSTudent/0ecacd6cb30cd57d419ba1280db4f8e3

Also, having optifine installed somehow fixes the issue

Hi. Can also say that its happening to me but not when trying to load/create a world. Rather when I try connecting to a server with this mod installed, I get a sync error and removing it worked.

This is my mod list

latest.log.txt
Client Log

And the error I get when I try connecting to the server