"Until next alarm" option missing in Marshmallow update?

I had been waiting with bated breath for the Marshmallow update to arrive, mainly because of the expected addition of the "Until next alarm" setting to the "Do not disturb" feature, but woe to me, no such luck! "Do not disturb" doesn't seem to have changed at all from Lollipop, and there is no "Until next alarm" option to be seen anywhere. What's going on, T-Mobile and Samsung? I have a really hard time using my alarm clock without this feature. Every once in a while, I forget to disable "Do not disturb" after I get up and then walk around half a day incommunicado, wondering why no one calls me. This is ridiculous! Doesn't T-Mobile realize how freakin' important this feature is to people?

Does anyone know anything about this issue?