Good point, but I think that for these guys, the ones that displayed this were the ones that were grooming themselves. Perhaps aggressive grooming resulted in self mutiliation? I'll take a closer look at the store tonight to see if any of them display it there and then observe whichever one I buy to see if it has these marks, too, once it gets home and has a chance to get healthier.
I have experienced two losses one never positively identified but best guess I got was Abdopus aculeatus. I had him for a week. He had been strictly nocturnal until the last day. He displayed a very light mottled grey color, the skin looked as if it would slough off if touched. He had obvoulsy lost control of his arms as they were cork screwed. Mantel didn't seem floppy but he had a difficult time keeping his head upright, it tilted to the side. He displays several of the characteristics mentioned as warning signs. Here is a photo just before death.