Twitch mode seems like you have to manually do one game of pure twitch mode, and after that twitch mode stays “connected” and will still be active in any game mode.
I discovered this on accident when we switched from doing twitch do a difficult deed and discovered that twitch mode was very much still active…
I have tried it extensively with Twitch mode now. Haven’t had any difficulties connecting it. It plays like any other custom/QP/deed with Twitch. (LFM Tweekly)