When Frank and his colleague are watching the video of Rebecca and her lover, Rebecca clearly mouths the words "Hey, shut up" before she puts her hand over the handcuffed man's mouth, however the sound is not heard, but grunting and moaning is.
After Frank drags Rebecca into a side room and yells "Why didn't you warn me at least?", Rebecca clearly begins to respond by moving her lips into an 'F' sound (presumably "Frank"), but then the camera cuts immediately and Rebecca says "Did you need to hear about......."
When Rebecca and Frank are kissing and fall back on the stairs, Rebecca removes Frank's tie, and then roughly shoves him away. Just before she pushes him, actor Willem Dafoe holds still for a split second, clearly anticipating/bracing himself for the shove.
As Frank chases Rebecca up the stairs, there is a wide shot in which he clearly tears her dress, however in the next shot the dress is intact, only to be ripped again, as Rebecca runs up the same stairs as the previous shot.
When Rebecca is holding the candle over Frank's chest and taunting him, there is a close up of Rebecca in which she moves the candle away from herself to drip the wax. However, in the next shot, a close-up of Frank's reaction, her hand is in exactly the same position as previously.
When Frank approaches Rebecca as she is lying on the bed and takes off his shirt, the cuffs of the shirt are suddenly unbuttoned (presumably so it would be quicker for the actor to remove), when they were buttoned previously.
Rebecca straddles Frank with a candle in her right hand and a bottle of champagne in her left. At one point, she allows him to suck her finger and runs her left hand over his chest. The bottle of champagne is nowhere to be seen, and there is no available flat surface for Rebecca to have placed it on. Moments later the bottle of champagne is back in her hand again.
When Frank follows Rebecca to her bedroom, there is a shot from Frank's point of view of him parting the curtain to see Rebecca lying on the bed. In the next shot, a close up of Frank, he parts the curtain again.
When Frank angrily follows Rebecca upstairs into her bedroom, just before he grabs her arm, reflected in a mirror at the top of the stairs the camera is visible, as well as a crew member wearing a white t-shirt and jeans.
A detective states that the reason the police called the District Attorney is because the victim, Andrew Marsh, was handcuffed at the time of death. However, in the opening scene it is obvious that the dead man is not handcuffed. Moreover, if he were, it would almost conclusively prove Rebecca's guilt - if she did not kill him, she would have untied him before leaving. And despite this supposedly being the sole reason for Rebecca's arrest and prosecution, whether the deceased was or wasn't handcuffed at the time of his death is never mentioned again, by anybody.
The second time Dr. Paley gives testimony, Frank asks him why he did not reveal previously that he had dated Rebecca. However, unless Frank's client had chosen not to inform her lawyer about information that was vital to her own defense, then Frank knew about the relationship too, and he chose not to reveal it, either.
At the climax of the movie, Alan Paley is chasing Rebecca up the stairs, when she kicks him in the face and he falls backwards, it is quite obviously a stunt double and not the actor. The double is much younger, and even has different hair color.