Minecraft Version

1.20.x

Forge Version

47.2.1

Vampirism Version

Vampirism-1.20.1-1.9.2

Modpack

Singleplayer/Multiplayer

Server

What happened?

2 zombies attack a vampire, this causes an error
message.txt

Relevant log output

No response

Reproduce steps

spawn two zombies near the vampire. They start beating him and this error occurs in the console

Other relevant mods

No response

The log entry is only a warning, and not an error. FYI: this happens when the player is attacked by the zombie.
There is not necessarily something wrong.