You should have said “Xbox, Record that” or double-tapped the jewel button on your controller then hit “X” if you don’t have a kinect hooked up.
Dude, I had similar thing happen to me like right now… I was playing slayer in Halo 2 (don’t remember the map); and got on of my, if not my best game… Then I went to theater, didn’t find Halo 2; now on the forums finding out there’s no theater for Halo CE or 2… Super disappointed. 343, if you’re still working in the MCC, add this super necessary feature… And bro trust me, I feel you :v