Other mistake: When the girls leave camp they wave good-bye to each other. If you look closely it is obvious that one of the girls (the one in the distance waving) is a double who does not look like Susan / Sharon at all.
Suggested correction: No one is waving in that scene. As a matter of fact, the one "in the distance" can't wave because both hands are holding suitcases. They kissed goodbye, not waved.
Continuity mistake: At dinner, after the girls' performance, when explaining that the girls had tried to replicate their first date, Maggie mentions the "violin music" before it begins playing.
Suggested correction: Hecky starts playing the violin (badly) before Sharon and Susan do their performance. That's the violin music that Maggie is referring to.
Revealing mistake: Susan's camp friend with the light blond hair continually repeats the last word or line of the person before her, or mouths it to be ready for her own lines. In the dining room when the twins first see each other, Susan says something like "Whatever can I do about it?" and while she's saying that, the other girl is mouthing the words, then says her own line. She also does it in the shower scene, where they're talking about revenge, the other friend of Susan's says, "Give it to her good!" then this mimicker says, "Good. The old coventry treatment..." It's pretty funny, and shows what child actors had to learn.
Suggested correction: Not true. The actor has admitted it. It's just a habit created by rehearsals. Very common.
Suggested correction: To start with the dining scene, she is not mouthing her lines, she only once moves her mouth a little but it wasn't to mouth the other girl's lines. And when she says "Good" she's not repeating the other girl's lines she confirming what the other girl said.
