Bug - Can't Exit Local Multiplayer Menu

I setup a game of Slayer, 3 players locally, on a Halo CE map. Works perfectly.

After the game, we see the results screen, with kills, deaths, etc by player.

However, we can’t find a way to exit this area to start a new game, or go anywhere else in the Halo Master Chief Collection.

Only options offered are:

- For Roster, that allows us to invite players or re-join, but nothing happens once we all re-join.
[Game Menu] - Career and Stats for the highlighted player.

“B” does not allow us to go back beyond this screen.

We’ve tried all other button combinations, and just can’t seem to get out of this post-game area.
Suspect a bug, or a completely unintuitive way to get back to start a new local multiplayer game (or reach the main Halo MCC menu) that we can’t find.

Did you ever find the answer to this? Starting happening yesterday and we can’t figure it out.