Anyone else had their rubber stoppers fail like this??

The other day I noticed this black thing on the floor. I checked my MBP and realized one of the stoppers on the bottom had completely come off. So I opened it up and found this, one stopper seems to be fine, the others have/are falling apart.

this one is ok:


this one is cracking:


this one cracked and missing part of the top piece (there's two pieces, the bottom stopper and this circular clip inside the case)


this one completed failed:

 

I just sg'd the one back on.... just thought it was odd how bad/quickly these things give out. I mean one completely deteriorated apart, def cheap materials used. The top piece inside is flimsy junk. Not sure why they went with this design as you can look right at it and think of a dozen ways to do it better. No biggie, just annoying lol.

 

No, haha I wondered what those were too.. there's a bunch of them all uniform and in a perfect line. Not sure what they are as I've seen other opened cases that didn't have them. But has to be from the factory as each one is the exact shape and in a line.