i am making a assumption but i did pin it down before and this was a issue before and idk if it now,
i think its a animation because i believe its a zombie riding a cow that it really hates

ths is the crash report:
crash-2021-09-16_21.26.25-server.txt

also have another issue but its going to be a seperate one as its completely unrelated to this issue, not game crashing or anything, this is.

It seems like the Optifine causes this crash but I don't have the authority to modify Optifine's code. I recommend not to use it for now.