Hey there,
I'm not owning a band, so I can't properly contribute to this thread with pictures, but I can't seem to notice how the rubberized parts look.
I own a Logitech Harmony One universal remote and it too has a rubberized bottom. I've owned it for more than four years now and I think it was after 2 and a half that the rubber started to show "wear and tear". It looks like the rubber got "warm" and my Palm was imprinted in it as you can see in the picture below. It looks nearly identical to the pictures of the OP.
And everybody should know that a universal remote is by far nothing that you hold for five hours straight in your hand so the sweat can change the structure.
(sorry for the ugly flash, but otherwise you can't see the warping properly)
I
never cleaned the remote with alcohol wipes, nor any other chemicals. The only thing it was touched by were my pretty normal hands and a soft cloth from time to time to rub off the grease that accumulates on the gloss finish. The rubber was never touched. The "tearing" occurs due to pushing around on the table but you should be able to make out the warping and change of structure where it usually gets hold. FYI: I never hold the remote on that spot with my palm, but nevertheless it looks or at least feels like it has that structure imprinted from my hand. You can see the "top" of the remote is perfectly clean and smooth because it's not used as much or because the rubber is different there.
Additionally: The battery pack sits in the black gloss bulk and partially where the rubber starts to warp. So in my personal opinion, it could be caused by that maybe?
Back to the Band:
From the reviews and pretty ugly teardowns on the internet I've come to understand that the batteries rest on the side of the band where that exact rubber disintegration is happening. Maybe the batteries are causing something like that? I'm no export on that but maybe it's due to the heating and cooling of the batteries that the rubber is not proper for that job?
Just throwing some ideas in the ring.
Regards,