There was something done in the 2000's that made all these things degradable. I had 20 pairs of echo shoes do it. They replaced them and the replacements did it.
All the Microsoft mice and keyboards from that time had a soft plastic coating. All degraded.
I have 8 JBL LSR 4328 Studio monitors and the 4312 subwoofer that had this rubberrized coating on them and they turned to goo. My 2002 Landcruiser armrests just starting breaking down. Really is ticking me off.
It turns into an absolute mess. The Navy's Bates shoes soles all do it. You can find a ton of pix showing high ranking guys at Navy ceremonies in socks. They don't wear those white shoes that much, few times really in their careers. They put them on for a ceremony and they chunk apart having only been worn a few times.
First I heard of buttpads doing it, but it don't surprise me. May be done in an attempt to make them bio degradable...