Deteriorating Thumb Grips??

I used to be performing some cleansing earlier right now and as I used to be returning my Xbox controllers to their little space on my dresser I seen this actually bizarre factor with the grips and I’ve no clue the way it occurred???

The final time I performed on my Xbox was about 9 days in the past, however once more, I'm not likely positive when this subject may have began as a result of that is on my older controller that I don't actually use as a result of the grip on the joysticks had smoothened out from how a lot I'd used it, and as you possibly can see within the 2nd pic, my newer controller's joysticks appear nice.

What's even crazier is that I simply pulled out my Swap Lite (which once more, I haven't performed in a sizzling min) to see which thumb grips can match the coral, and the identical subject is on each joysticks! Besides the left-handed one is worse than the opposite. Can somebody please let me know the way this might have occurred? I'd actually prefer to know if that is one thing I can keep away from so I don't have the identical downside w/ my final remaining Xbox controller 🙁