Okay, so I got problem

So I finally decided to play this game on hardcore mode to see what it was like, Suffice it to say it made an already cool experience even better. anyway, I was on the wasteland finishing a mission when I was suddenly attacked out of nowhere by Caesar's Legion, I killed them since I never liked them anyway and just for fun I decided to steal one of their armor and put it on. it gave me good defense but I mediately took it off because it was too heavy. anyway, once I made it to an NCR outpost all of a sudden they attacked me. I wasn't wearing the armor; I had even thrown it away, so what the hell? what's worse, is that two messengers had come: one from the NCR and one from Caesar's Legion, both telling me that I had been pardoned for any transgressions against them. but once I went back into the NCR outpost I was attacked again by NCR officers, is this part of hardcore mode or something? or is this a glitch in the game? I play on a ps3. so if anybody can help, please and thank you.