Just an idea that came to me recently, I don’t know how feasible it is. However, I was thinking if someone took the clip of Kylo suggesting a clone army in TFA and re-purpose the line to him saying “a clone” when encountering Palaptine. I know his voice is modulated in TFA and he is maskless in TRoS so it may not work. If someone could clean it up, it could make Kylo seem more intuitive and help explain further in the film that the Palapatine we encounter in TRoS is indeed a clone.