I have probably 80-100 pieces of that same PPU brass in .308, and I see that slight shine around the ejector also on some of my rounds. In my case, I am pretty sure that it is from the factory load, not my reloads. My typical load is 43.1g of 4064 under 175g bullet @ 2.8 OAL. That load is well within published load data.
The one thing that I did notice with the PPU brass is that the actual thickness of the rim is significantly larger than other brands of brass. I actually had to buy another shell holder for my hand primer because I had to pull the priming tool apart about 10% of the time to remove a PPU case. The shell holder was obviously on the low side for rim thickness of course, but no other brand of brass would stick in the shell holder like that. Maybe that rim thickness has something to do with that ejector mark? Are the rims on your PPU brass thicker than other brands of brass?