It’s funny how this issue is all over the internet yet Apple haven’t heard of it before
I have similar problems and will contact Apple about it this week. Sometimes when I adjust the headpones there is an electric click sound and they turn off and come back again after a second or so. Sometimes only on one side.
After this happens they seem to sound a bit different like it’s affecting the noise cancelling or adaptive EQ. Mostly affecting the bass I think. On a few occations only on one side which makes the balance sound a bit off.
A reboot fixes this until it happens again which can be ten minutes later or a few hours later.
If I don’t touch them or adjust them they’re usually fine but it has happened on it’s own or by me just moving my head a few times.
Edit: I've had them for about two weeks so they're pretty much brand new.