Critical Role has already been operating under a different set of rules for a while now.

It's been against the Twitch affiliate agreement to be simultaneously broadcasting since at least 2019. (The last time the terms were updated as of right now.) https://www.twitch.tv/p/en/legal/affiliate-agreement/

You're supposed to give Twitch a 24 hour exclusivity period for all newly streamed content - whether pre-recorded or live.

Critical Role, obviously, has not been doing this. Presumably they will continue under whatever alternate agreement they already have in place with Twitch that's been allowing them to break this rule for at least three years.