It happens also when you go through End Portal in the End and maybe other interdimensional process of teleporting a player by killing him/her.
I'm using Mohist and running Stacia Expert.
Here is logs after I died in the Nether.
logs.txt

If this doesn't happen with a standard Forge server, it's Mohist's fault (and their job to fix) instead of ours. Feel free to report it to them!