After last night I am buying into the theory there are two Mr Robots, there's the more aggressive one we see in the baseball cap (like his real father) and the other one that is more calm, sympathetic and protective (his idealised father) that never has a baseball cap on.
Cap Wearing Mr Robot "pushed" Elliot off the Rocks, threatened Romero with a gun, and intimidated Krista during a therapy session.
Non Cap Wearing Mr Robot stayed by Elliot's side when he was suffering through withdrawal, consoled Elliot during his prison beating, balked at the idea of manipulating Olivia and was the one in the last scene last night.
In other words, the third persona has been hiding in plain sight since season one and Mr Robot hasn't actually had wild mood swings they're different personas.
I think you are wrong. It's the same person, since idealized personalities are always made of contrasting opposites. Loving and protective father must be aggressive as well.
Edit: After watching today's episode yep you're right I'm way off base.