Other player can't control anything in Remote Play Together since it's update

[Nago]

ISSUE
I've played a lot of games in remote play together with my friend, but since a few days (I think since there is the new remote play beta) he can't control anything with the keyboard or gamepad. We have tested many games that worked before, but none of them works now.

OS
I have Windows 7, the guest have Windows 10. We have tried it reversed, when the Win10 was the host, but still no input was recognized from the remote player.

STEPS
Start a Steam remote play together compatible game.
Invite friend to play remote play.

RESULTS
Remote player can't control anything with keyboard or gamepad.

EXPECTED
Remote player should have control like before.

[slouken]

Mouse and keyboard sharing is disabled by default, but can be enabled in the Remote Play Together dialog that pops up when a session starts.

[Nago]

I know. If I enable them they still don't work.