In the first bathroom scene where Aedan has a bath, he gets into the bath wearing grey underpants. However, when he gets out he is wearing dark blue underpants!
Yeah I noticed that too! When I asked my mom she said that maybe when he got out they were a dark gray because they were wet. I think that they were dark gray when he got out, but it did really look like blue.
Ok, I'm sorry if I happen to be wrong, since I haven't had a chance to see the movie, but don't you think that maybe the grey darkened to become a color that appeared bluish? Just a thought.