The entire right side of my headset is not attached to anything. It is still all in one piece, however the part with the notches (for indicating headband adjustment steps/measurement) just slides around instead of clicking into each notch.
I can even very easily pull it out, and nothing looks broken, and there’s no rattling or cracks. I have never thrown or dropped the headset, and I always keep the headband adjusted the same exact distance. I only noticed it because I accidentally pushed the cushion out of place, and was trying to put it back on, when I felt the whole right side just slide out.
The cables are still attached and both sides still work fine, no sound issues.

P.S. It is sadly long past warranty. I just want to know what on earth could’ve caused this.