Prob with raising in hand 2 is that it's still technically 3-handed and the player who originally opened could think it's clever to slow play big pairs post flop. If you were to raise here, if you get any pressure from him, you gotta put him on a big pair.

If he's doing it "so often" then it definitely doesn't mean that he has a big hand, so he's just doing it 'cause you aren't prepared for it and it's working. So adjust your play. You don't play against his raises, you play against his ranges. If the raise does not indicate a range that beats you, then rejoice and get that dude shoveling his money in when he's behind more.