I am guessing the arrow in this copy of your image is pointing to the area of the frame where the mark is being made. Right?
My plastic (PM40) Kahr has some light marks on the frame in that area, but none close enough the upper edge to cause a divot.
To get Kahr's attention, you will probably need a better picture of this area to help them understand how deep the divot is.
Personally, I would file a little material off the corner of the barrel lug right where it is contacting the frame with a round jeweler's file, polish the area if it seemed rough, and move on. But, that's just me. I sometimes do things to my firearms that other people would balk at, so don't necessarily take that as a recommendation.
However, I'm pretty sure Kahr will tell you there is no problem with the small amount of marking we can see in your picture of the frame. There is no real stress on the frame at this point and the barrel lug is very strong.
Best of luck and please let us know how it goes!
It would be so nice if something made sense for a change.
-- Alice in Lewis Carroll's Alice's Adventures in Wonderland