When both police cars pull up to the curb, the lead car parks directly adjacent to a fire hydrant (illegal). Later, when they pull out and leave, the hydrant is no longer there.
When Connie/Patricia first visits Steve at a motel, his room is on the ground floor, but when she returns later the same day, his room is on the second floor.
In the scene where Bill goes into Connie's room to find her packing, he buttons his blazer before sitting down to make a pro/con list. Later, while still making the list, his blazer is unbuttoned. (1 hour, 4 minutes into the movie)
When Paco goes to talk to Connie at the train station, the position that Connie holds the baby changes in between shots
In the bedroom as Grace says she "didn't like the nails," Connie's hand that Grace is holding changes positions in between shots.
When Connie is going back to New York, the train that pulls into the station is an MBTA (Massachusetts Bay Transportation Authority) train. No MBTA train goes to New York.
When Connie asks where the train is going, she is told that it is going to Boston. The passenger car exteriors have stripes of purple and gold. The only passenger service that goes from New York to Boston is AMTRAK and their colors are red, white and blue so it cannot be a Boston bound train.
At the end of the movie when Patricia/Connie is standing outside in her wedding dress there are visible tan lines on her chest in the pattern of a bikini or bra top.
When being pushed into the train, Connie says, "This isn't the subway!" but her mouth doesn't move.
During the "Sunny Side Of The Street" rendition, Connie joins in with Mother Winterbourne, but her lips don't seem to start moving until a bar or so later than her voice.
When being pushed into the train, Connie exclaims "This isn't the subway!" but her mouth doesn't move.
When Connie tells Steve she is pregnant, when Steve is talking to his friend to get him to confess to sleeping with Connie, there is a clear shot of a camera man and camera over his shoulder.
While eating lunch, in successive shots Connie and Bill move from Boston Common to Paul Revere's House to the Public Garden, then back to Revere's House; while the Garden and the Common are adjacent, Revere's house is much farther away from them than implied.
When Connie is talking with the homeless man at the train station, he hands her a sanitary wipe and as she wipes her hands her nails are painted bright red (no chipping)and manicured nicely. This seems a stretch as she has been living on the streets for nine months, with no money for enough food let alone nail polish.
When Connie sits down to a meal of soup eaten according to proper etiquette, the bowls of soup are tilted AWAY from the diners. Then the older Mrs. Winterbourne (Shirely MacLaine) is offered her medication by the chauffeur who takes away her wine glass. She says, ungrammatically, "Who is working for who?" It should be "whom".