Continuity mistake: In the scene in Frank's basement the ends of Rachel's scarf change: Before she picks up the sword the right end is longer, afterwards the left end. In between there's a close-up where she is holding the sword in front of her and where both ends are at level.
Continuity mistake: In the scene at the Miami hotel, when Rachel and Portman are in her bedroom, someone gives Frank a fresh drink of orange juice. He takes a deep sip, the camera cuts to Rachel's bedroom door, and when it cuts back to Frank the glass is even fuller than when he got it.
Continuity mistake: After Frank has moved into Rachel's garden house he comes to check Nicki's apartment. When he looks at a wall with some photographs there's a close-up of an old picture of Rachel and Nicki performing. In the close-up there is a pattern of light and shadows on the wall which was not only not there in the previous wide shot but which is also only visible on the wall and not on the photograph.
Continuity mistake: The bar scene of Rachel's and Frank's date contains a lot of editing flaws: 1) Rachels position switches between both arms down and chin rested in hand, 2) in one shot from the back we see her lifting her glass to her mouth, but when the camera angle changes she's not drinking, 3) the way Frank holds his glass switches between full hand and thumb plus two fingers, 4) Rachel's bangs change between straggly and fluffy.
Continuity mistake: At the end of their date Rachel and Frank come to his place. We see her checking out his basement with a wine glass in her right hand. When she picks up a picture from a shelf she holds it in both hands without having put down the glass before. A little later we see the glass standing on the left side of the shelf where she obviously couldn't have put it down. Finally, when she takes the sword from the wall the glass has miraculously moved to another shelf.
Continuity mistake: At the end of Rachel's and Frank's date the camera pans from the sword over some of his basement items on the shelves to the couple nestled between the sheets on the sofa, where Rachel states that never in her life she has felt as safe. However, when they wake up in the morning they are lying in his bed upstairs, and Frank opens a window that overlooks the garden. Considering their obvious comfiness downstairs this change of location can't be explained.
Continuity mistake: In the scene where she takes him into the boutique, she goes into a dressing room with a curtain across the opening. The shot pans from looking over the curtain, where it has 5 ruffles, to Kevin Costner and then back over the curtain which now only has 3 ruffles even though she hasn't come out.