This bug already exists for ages. It happens when the server's and client's position get out of sync. Yet nobody could show us how this bug occurs and we're also clueless what happens when somebody accidently noclips through a wall. Therefore we have no idea how to fix the issue.

Any ideas on how to reproduce the bug?

Well, I was thinking for a bit, and I think I know how this bug works. When I usually attack someone, my player changes position. In this case my team mate attacked and his player changed position into the wall.
He couldn't move, he was stuck in there.

I'll try to do the same thing as my mate did. Hopefully it will work, so I can show you guys

Alright, please let me know when you've managed to reproduce the bug.