It's a warranty coverage. Kia will have to approve. Then the dealer replaces the whole seat, I believe. It's been done for the bolsters getting worn out super early. Not very many cases though, on the forum. I haven't seen any new ones in over a year, till now.
It all depends on the quality of the hides - I was fortunate that mine came from some grass-fed red Napas. They spend more time on the range, and less time online, so they tend to have a thicker skin.
I have an approved " replace" for my drivers bolster , I'll do it in the next year . Its not that bad but I jumped on the issue early when some of our Aussie Brothers and Sisters were having issues and made a claim .................