At only 626 yards a 180 from a 7mag would have plenty of velocity to exit if it did not expand as shown in the pic. I don't know what happened here but something is wrong.
Both those bullets look just like some I have recovered from dirt from very very long distances at targets, all subsonic, bent noses and flattened on the side as well as a color from tarnish.
Here are how they perform for me just this season.
I wish I could be of more help but all I can say is I have used them for years now and been there for literally close to 100 kills and never seen anything like you are reporting. I to think you should contact Berger, they will want to help.