[2022] LAG

Originally posted by Chimeric: a friend of mine has this problem and it goes away when he plays offline. I've seen people talk about it here, I don't that have that kind of expertise but it was something related to the game needing to connect to a server for the functionality of coop even if option is turned off or as friends-only and you are alone in your world.

OP can try it, if offline solves the problem I find it unlikely is a game engine or pc thing.

There are no "servers". When you play online co-op, you're directly connecting to another person.