We are currently working on a fix that will enable archiving of Until Dawn Twitch streams as this feature was unintentionally disabled.
We are humbled by the community reception of the game and are excited to see fans sharing experiences on Twitch and YouTube. We apologize for the inconvenience and will provide an update as soon as the issue has been resolved.
This makes a lot more sense now. I thought it weird that Sony wouldn't have said anything prior to release. I hope this is resolved asap.