After their dinner date at the beginning, Grey sends Steele a message "Dream of me". Her reply is "Maybe. Thank you for tonight. Laters Baby". But when she sends a message to him about going to New York, Grey's chat history reveals her reply as "Always".
Before the masked ball, Anastasia is seen by Christian to be wearing full lingerie, but then at the ball, when they go into a private room to have sex and he strips her, under the dress she is wearing only knickers, the bra, suspenders and suspender strap are missing, but from the previous shots seen, there wasn't any scene showing or hinting to her removing those garments before entering that room. Especially noticeable since the later scene occurs not long after they arrive at the party.
Ana's hair is not wet after walking in the rain at night and stopping.
When Ana goes into the unlocked Red Room, there is a lever type handle whereas there was a round doorknob in Cincuenta sombras de Grey (2015).
While playing pool in the library of Christian's penthouse, when Ana is about to pot the fourth ball, she bends in front of Christian. He places her hand on her side, but as the camera pans out, he is holding the cue stick in his right hand.
While playing pool in the library, Ana shoot a solid red ball in the corner pocket. Then she shoots across the table to another red solid ball. In Billiards there's only 1 solid and 1 stripe of each colour.
In Christians apartment, several 'set' items changed from the first movie. Even though the writers want you to believe the second film's story picks up shortly after the end of the first film's ending. The art piece on the window wall changed. The large table in front of the window where in the first film he states that he's "Fifty shades fucked up" changed. Most visually obvious was the fireplace. This second film has a much larger one and now there's a TV above it where there was none in the first. The design of the staircase changed dramatically. The door to the playroom was white, but now it's dark.
It's implied that Christian's room in his parent's house was his as a teenager and unused for some time (He says it was his room "once upon a time"). However, some of the books are too new to be his as a teenager: The book, "Kill City Blues", by Richard Kadrey, was published in 2013, when Christian would've been 25, and "A War of Gifts" by Orson Scott Card (2007), when he would've been 19.
During the photo exhibition scene, Jose takes Ana's glass of wine and looks to take a sip, but the wine never touches his lips.
As Christian and Roz approach Mt. St. Helens in the helicopter, they first see it approaching from the northeast as if they were flying southwest toward Portland from central Washington. Then, they are seen flying north around the eastern face of the mountain, with Crystal Lake in front of them, in the opposite direction from the previous shot. Neither of which accounts for why they were anywhere near Mt. St. Helens in the first place. It's nowhere near any convenient flight plan from Portland to Seattle.
Although in the movies Christian says a)He claims that he doesn't remember his mother, but there is a photograph in his room of his mother and his subs are supposed to look like her. b)He says that he was with his mother when she died and then taken to the hospital where Grace was working at the hospital which led to his adoption but doesn't really explain how he ended up in foster care with Jack Hyde.
When in the gym, as Ana asks Christian how did he sleep, Jamie Dornan loses his American accent when saying: "like a log, out all night"