I had this same exact issue I got a replacment unit before my warrenty ran out years ago. Now the replacement unit suffred from the same issue. I discovered the issue is the power switch gets worn down after many on/off cycles you can either replace the power switch or dissasmble the headset and remove the buttons/power switch cover then reassmble the headset without it now the power switch has full range to switch on/off.

I managed to fix the power switch. I took it apart and disassembled the switch. There is some sort of oxide layer over the contact. I took sand paper and went at them till they where shiny. Haven't had issues for months now.

I had the same problems with the G935. They didn't fix the issues so probably intentional. The headband cushion I managed to just shove back in. For the power switch, I found a reddit guide that got it mostly fixed (search for "G933 Sound Unbalanced? Power Button Fixes?"). Basically you take it apart, and then use your screwdriver or something and gently press down on the housing around the power switch. It just tightens it up a bit. It may feel like you're not doing anything, but it's helping. Then put it back together and it should help. To prevent it from happening again, I've just started never turning off my headset and setting the idle time to 15 minutes so it doesn't completely drain. Plugging in the USB headset turns it back on, but since that's a huge pain, I've been using magnetic USB charging tips (you can get a pack on Amazon for like $20, I use it to charge my keyboard, mouse, and game controller too), so it's literally just a snap to plug in the charger.