In Jungle Boy, while Pink Guy is rapping he randomly leans over and starts screaming incoherently. This is followed seamlessly by the line "So do you feel high?"
In FILTHY FRANK VERSUS ANIMAL RIGHTS, Impostor Frank is shown trying to get the approval of an animal rights activist for a video. The video in question involves betting on whether or not a snake will eat mice, with a Gory Discretion Shot whenever the snake eats one of the mice. Regular Frank probably would've posted the video unedited and without considering approval, but not Impostor Frank.
In FILTHY FRANK VS CHINCHIN Fake Frank's sexuality is listed as being gay. In other words, the impostor is "Fake and Gay!"
In UNBOXING WEEB SHIT after Joji post-edits saying that he genuinely didn't care anymore, for the last segment Frank broke character as Joji was the one who was saying all of the things to the lower part of the mannequin. We know this, because his rant involved Japanese women saying to act more full. Knowing that Joji is half Japanese, it's possible that when he was in Japan he suffered this sort of discrimination for not acting "Japanese". The "roast" at the end really was just Joji ranting on the flaws of Japanese culture under the Filthy Frank persona.