Continuity mistake: When Ana and Christian prepare for the masquerade, Ana is wearing sexy underset comprising corset, stockings and everything. After the party when they start having sex, Ana wears nothing but underpants underneath her dress.
Continuity mistake: When Christian and Ana are making out just before having sex for the first time, Ana's hand is on the back of Christian's neck when the camera is facing her. Then when the camera is behind Christian, her hand isn't there, and it goes back and forth until from behind Christian we see her hand slide around his neck.
Continuity mistake: During the "road-map" scene when Ana first puts the lipstick on Christian's chest, you can see the lines are not exactly neat and straight, but when they're in his bed together, just before Christian was informed that the guy was there to do Ana's hair, the lines are now much straighter.
Continuity mistake: When Ana was reading the card with the flowers that Christian sent, she is holding it behind the vase and below the flowers. When the camera angle changes, the card is now suddenly above the flowers.
Continuity mistake: When Jack is at the masquerade ball, he takes a photo of a picture of Christian and his family. If you look at his camera, you'll see that the frame is barely being taken. However, when Jack looks at it at the end of the movie, almost the entire frame can be shown in the picture. He had no reason to take another photo, and he left right after taking it.
Continuity mistake: Just before Christian's helicopter crash, you can see that he's got a little stubble on his face. After he comes home - on the same day - he has more stubble, and is wearing a different shirt.
Suggested correction: Some men's stubble grows relatively quickly, I know a few men that can have a full on 5 o'clock shadow by noon, and he might have changed his shirt from a gym bag or from anywhere, since the shirt he was wearing when the accident occurred may have been pretty torn up.
Continuity mistake: The staircase in Grey's penthouse is completely different from the first movie to the second/third installments. In the first film the railing is enclosed and the steps open like a ladder) in the second one the railing is open and the steps are stacked like blocks.
Continuity mistake: Ana and Christian are at the helm of the boat. In the first shot they are both wearing gloves, next shots they are not.
Other mistake: Both Leila and Ana have the same SS# listed on the cover sheet of the files Christian keeps on all his submissives. 123-45-6789; Also, Ana's info has 2 paragraphs that repeat over and over in her file.
Suggested correction: Regarding the SS#: Good catch but this should probably be classified as a "Deliberate" or "Revealing" mistake." The 123-45-6789 is not a real SS# and has never been issued. Using a second different number would expose a real person's SS#. The filmmakers likely opted to avoid that and any potential legal issues that duplicating it could cause. There are additional SS# combinations that are never issued, such as ones starting with "000" or "666", plus a few others, but those would look fake. This is similar to how movie phone numbers often start with the dummy "555" prefix.
Other mistake: When Ana received her flowers the card facing her says Christian Grey Enterprises, when she reads the card to see who they are from it says Christian and she contemplated putting the flowers in the bin. Ana would have known they were from Christian when she answered the door because of the business card facing her.
Suggested correction: Who ever said she didn't know who they were from? When the delivery man gave her the flowers, she gave a look as if she knew they were from Christian and was probably thinking of him while looking at the card. Nobody said she didn't know who they were from, or that it was "revealed" to her, because who else would be sending her flowers, especially after a break-up?
Suggested correction: Just because it's right there in front of her, doesn't mean that she saw it, or registered it.