-snip-
her hair goes from behind her back, through her arm, and over her shoulder
in one fell swoop
yeah and it's barely noticeable when you're watching it to enjoy it and not looking for mistakes so you can cry "omg animation fail lol!!"
like if we're gonna nitpick then how about that one time in wreck it ralph when the villain dude's (turbo??) tongue clips through his bottom teeth when he talks? that wasn't done to make it look more fluid. that was an actual error.
frozen's "animation fail" was done to make the motion look more fluid.