Young Sheldon season 4, episode 15 has created a plot hole about Sheldon and Amy's future. The episode's narration hints at events taking place in the present time, around two years after The Big Bang Theory ended. However, this contradicts the timeline established in the Young Sheldon season 4 premiere where adult Sheldon reveals that he and Amy have a son who has already had a graduation party. This would not be possible if Leonard Cooper was only one or two years old. While it's possible that Sheldon is telling his childhood story out of order, the show needs to be more careful with details like this. There is potential for Amy to make another cameo in the future, given the working relationship between Jim Parsons and Mayim Bialik in Call Me Kat.