Problem/Bug Server Crash When 1.17 Chunks Don't Load

Hello

I'm admin on a small 26 member private SMP, we've recently updated to 1.17 (from version 1.16) though not without issues.
Whenever a new 1.17 chunks are loaded (via to going trough the nether portal, we haven't been able to test teleport yet but flying with an elytra works fine) none of them actually load, mobs spawn but blocks are invisible, the player can't move but chat perfectly fine, after a while the server crashes, when it restarts the chunks load but the nether portal the player came trough isn't there.

This is very annoying as everyone of course wants to get copper and stuff and admins need to help people back to the nether all the time, has anyone else experienced this? How do we solve it?

- Me

 

I'll suggest it to the owner