Looks to me those rounds fired out of battery. Ive seen that before. I had issues with CCI Large pistol primers, that would slam fire in my Thompson (heavy recoils springs with high bolt force), and they put bulges in the case like that from not being fully in the chamber. Once I switched brands - the problem was gone.
Ive also seen a Luger (9mm) that fired out of battery, do the same thing.
Nope, These were 9mm shot in a 40. I have seen it done twice before. If the were fired in a 9mm that was out of battery the back of the cases would be blown out. Kinna like a unsupported 40 pistol bulge, but the bulge goes all the way around the case when fired out of battery.