@hutaffe I've seen it for all kinds of videos but one example I just came across: TennisForFree tweet

There are some kinds of vidoes that play... in Moments. I'm not sure if they're uploaded differently or if it's because they're in Moments. Of course Twitter wants to spend exactly 0 effort in making any of this transparent; "just sign in and don't worry about it" I imagine is the party line, as with all of the silos.