I have the same headset (AKG 553 MKII), it broke after a couple months, I got it replaced, and its almost broken again (earcup nut w/e broken same as what you described) just seems to be a badly designed headset in terms of durability; just normal use seems to be enough to break it (I never dropped either).
(I am not really into headsets, I just noticed this post while scrolling down and how I had a somewhat similar experience)
BiC_MC t1_j6i6t2v wrote
Reply to RIP to AKG K553 MKII by Regular-Mousse7841
I have the same headset (AKG 553 MKII), it broke after a couple months, I got it replaced, and its almost broken again (earcup nut w/e broken same as what you described) just seems to be a badly designed headset in terms of durability; just normal use seems to be enough to break it (I never dropped either).
(I am not really into headsets, I just noticed this post while scrolling down and how I had a somewhat similar experience)