Which game mode are you asking about?
I know some pets were limited access, so you can't get them and use them anymore. Some pets are broken on some servers.
I'm not too familiar with survival this season, but last season there were a bunch of broken pets. Perhaps they just got overlooked when they were updating the game.
I don't think pets on survival work right now. I'm sure it's already a known problem but it's not really high on the priority list since it's purely cosmetic. I know disguises don't work for sure, but if pets don't work I wouldn't be surprised