He was already not joining the collab even before he did that stream, though. This Tweet was from yesterday. He originally was supposed to be in it though.
Yeah I believe he wasn't planning on being in it from the get go. I think I may have the answer as well!
Axel mentioned that two managers are there while he's cooking. Vesper was going to originally be there with Axel cooking, but the same manager that he got into a fight with over the fucking XCOM perms happens to be there. And unfortunately for Vesper, there is a restraining order filled against him so he can't be there. Otherwise, Vesper was going to take his spear and make shish kabob out of him. Completely 100% real.