There’s a magnetic contact that the “bra” case engages that turns off the headphones so the battery doesn’t needlessly drain. Bunch of companies make after market cases/covers, you should get one of them at least.
I am aware of how it works, that's why I front-loaded the part about the brassiere being MIA at the moment. I just don't care, and I don't take it outside except on the airplane. Next flight I have, I'll probably dig out the brassiere.
Also in my experience, the brassiere was never perfect about guaranteeing the AirPods Max were put perfectly into a sleep state. The same exact issue could sometimes occur, maybe an alignment issue. The AirPods Max sound fantastic, but there's a lot of little details about them where Apple just kind of dropped the ball.
