This happened multiple times on my server, when I would crouch the server would crash with the following report. We could fix the ticking loop by having another player teleport mine right as I log in, it would crash again but would reset the ticking issue. Originally thought it was an animation issue but after testing I've narrowed it down to potentially the skills. Based on the line: at net.minecraft.world.entity.player.Player.handler$cce000$sedparties$isInvisibleTo(Player.java:13280) ~[server-1.20.1-20230612.114412-srg.jar%23905!/:?]
I am thinking that the stealth perk that allows invisibility while sneaking might be causing this crash to happen, seeing as it would happen when I would crouch but only after I had acquired that perk. To try and confirm once we were able to get me into the server without it crashing I used the Malevolent Manuscript to reset my skills and didn't have any issues after when crouching, not yet anyways.

Obviously this issue could also be other mod conflicts as well, was just having issues figuring this one out.

Bellow is the crash report generated by my server, the other crashes from what I could tell looked exactly the same, hope that if there is an issue this might help! Let me know if the attachment is bad.

crash-2024-11-03_23.24.10-server.txt