I know the is an old post but I think I may now have the answer. I've been shooting new Remington Brass in my Remington 06. The old brass, from the 70's I've had no problems with even after 8 to 10 reloads. However after about 8 relabellings some of the new (purchased last year) brass started blowing holes at the edge of the primer pocket. I threw everything away that was loaded 5 or more times and broke out a new batch. I prepped 30 new cases. Annealed, full length sized and chamfered inside and outside of the neck. 2 of the brand new casings blew holes. Now I've been using the same load for years. There's never been a sign of overpressure and the old brass has held up just fine with no holes blown in the primer pocket edge.
My bolt face shows the same piting as those pictured. Seems someone else had problems with holes being blown in the primer pockets.
Strange thing! I just received a custom 308. I loaded 20 rounds of once fired Winchester brass. Peeped it and loaded Lyman's starting load (43.0 gr. IMR 4064) for brake-in purposes. 2 out of 20 blew holes n the primer pocket edge. I've shot 50 new, prepped Nosler cases for latter testing five of which were max load (48.0 gr. 4064) with no problem. I now have two pits in my brand new bolt face.
Anyway that's what the pits pictured look like to me.
Guns are not dangerous! People are! RKBA!