stearing wheel buttons

I have had problems with my buttons cracking. Please everyone reading this that have them go out look really good and see if yours are cracking as well.
This will be my second set relaced under warranty. I have a fealling that it is due to heat and plastics issue.
It's starts as a hairline crack and gets more noticeable over time. I have a 2006 model and got it in april of this year.
I have looked at a new one on showroom floor and it has it also and does not have more than 15 miles on it.

thanks