In his note to Mirabelle, Ray's narration does not match what's written on the paper. Along with skipping some words in the middle, he wrote "because you asked me to," but he narrates "because you deserve to know."
The card that Ray sends to Mirabelle reads "I would like to have dinner with you" in block print, with a signature at the bottom. When we see this card again at the very end of the movie, the signature has been replaced by "Ray Porter" in block print.
When Jeremy come back from getting a condom you can see Mirabelle sitting cross-legged with her elbows at her knees in the mirror reflection, but the immediate shot afterwards shows her with her elbows resting on her upper thighs and positioned much closer to the wall. Then she leans back with her legs to the right, but on the close-up, her legs are now going to her left.
After Jeremy and Mirabelle sleep together, they are talking in bed under a sheet. Jeremy has his arms completely above the sheet. The camera angle changes and now the sheet covers his entire body up to his neck.
In the scene where Mirabelle is at her parents home in Vermont and takes a phone call from Ray, the camera cuts to a shot of her mother sitting at the dining room table. Behind her mother, green, leafy trees are visible through the windows, even though everything outside the house was covered in snow when Mirabelle first entered the house.
Early in the film, the camera pans up and we see Mirabelle through her bedroom skylight window. The bedroom is clearly positioned about ten feet or so from the left wall of the apartment, suggesting another room between it and the left wall. Yet in a later shot from the ceiling, when Mirabelle lies in bed with depression, the left wall is right up against the bed and there's a window there looking outside.