I thought I'd check back in with some subsequent findings.
I ran the lighter loads (37-39) and still saw the same issue, but to a slightly lesser extent. I then read an article about over pressure that was linked to in another thread. It talked about the presence of liquid causing higher pressure.
In my initial research, I'd established a significant level of paranoia regarding lubrication to prevent case getting stuck in the die. I'd overlooked the point that you don't need to lubricate when seating the bullet. I believe the lubricant was causing some over pressure, plus the case couldn't grip as well.
On subsequent load builds, I'm not seeing the same level of scoring and my bolt lift isn't an issue. 40Gr appears to be the sweet spot.