Again if it was another mods entity then i would agree. However it is an unused data watcher on the player. Hence another mod must be trying to also use it if it is crashing.
Please actually take a look at which entity is crashing before blindly solely blaming me.
Anyway this is an old mod from when I was learning to code but I still don't like that I was solely the one you were blaming for changing something vanilla
(Only just had noticed this response and didnt like that it was left at that)