I got that with almost all of NOE's top punches, but fortunately they are made of relatively soft Al. and I was able to take my jack knife and relieve the edges,
all is well now.
You can also just whip up a new one in the lathe. I did that for my 300 BLK, I grew weary of the little ring.
For some reason the manufacturers like to leave a sharp edge somewhere in the searing stem.
dig around in your old pile of rcbs seating stems and find a flat one and put it in there.
barring that a wad of aluminum foil will fill in that rounded portion.
but that's ugly.
I think your stem has a poor finish on it, I'd lock a couple of nuts together on the stem and spin it in my drill and use some crocus cloth wrapped around a pencils eraser to clean that up.
Not certain if he still has them available, but at one time Buckshot made hollowed-out seating stems that could be filled with 2-part epoxy and then nest a bullet coated with release agent in your sizer.
Long ago I ground off the ridge on my 38/357 wadcutter seating stem to make a true flat engagement surface. Marred bullet noses REALLY annoy me.