Then I must be living a charmed life as I have 10s of thousands of cases through my bolt guns that did not exhibit that condition. Just maybe it is avoidable.
It does look like it is extraction related though. If it were on my brass, I would be looking at the chamber to make sure that there wasn’t a burr of small piece of brass in there causing that scratch. Actually I’m making the assumption that it is a scratch based on my phone’s limited ability to view those pictures more closely. To me it did not look like a dent as much as a scratch.
I once was experiencing a vertical scratch on my brass in the neck area. After ignoring it for a while, I started by addressing the neck area of the chamber with a good cleaning. After some careful scrubbing, I removed a small brass flake embedded there.
To the OP, is this a new rifle or did this just start happening?