This problem also occur when you are pushing too hard on the cutter. The cutter have to do his job by letting it do the cutting. Pushing too hard - swage the lip of the brass instead of cutting properly and cleanly.
You can order a new cutter head directly from Redding. But to have a dull cutter, you need to have cut thousands and thousands of case or have it damaged in some way.
I do not cut any of my case to minimum. I cut only case that are over the max. I cut more often, but a lot less material is removed that way, it’s faster and case fit better in the chamber.
Another benefit, carbon do not build up and create a ring in the end of neck area in the chamber.
There is simple tools avail to check your chamber - neck oal. It’s a simple button that fit in a shortened case. This showed me over time, that chamber neck are generous in non custom barrel.
