Earpad velour has come undone. Weak glue. (It was the off center bottom disc creating weak spots). Gonna go to Aliexpress, I guess. If the quality doesn't hold up, no biggie. At $7.64 a pair, I'll just buy another or maybe upgrade to the $8.50 pair.
edit: Dekoni has sent me a new pair with no hassle.
Sidebar: 1 pair arrived from China. They were angled, (I must be blind and half deaf), came with their own attached foam but no attachment disc. I cannibalized the remains of my bad pair and tried them. I knew my hearing had dropped in the treble but with this foam I discovered what I had been missing. These would have been fine except for the suck-out in the mids. I used some speaker cloth with my replacement Dekonis 'and my 650's are better than ever. Thanks Dekoni!