At the bar, when Angie makes the fighter spill his beer, the fighter has foam on his mustache. In the next frame, it's gone.
When John and Angie are at the bar, the amounts of stout in the two glasses change between frames.
All of Lesley Ann Warren's dresses -- especially her evening gowns -- are far too short for a young lady of her age in the 1910s. The only possible exception is the pleated red skirt she wears in the initial scenes.
When the scared maid is drinking her coffee in the kitchen and her seat is lifted by one of the Alligators, the wire lifting the seat is clearly visible.
In the opening scene, the camera appears to look East on Walnut Street, past Rittenhouse Square, with the tower of Philadelphia City Hall in the distance. Cars are shown on a drive in the square. No such drive ever existed. City Hall is on Market Street and the tower would have been outside the frame of this shot.
The Biddle Mansion at 2104 Walnut Street is shown as being directly across Walnut Street (the north side of Walnut Street) from Rittenhouse Square. In fact, Rittenhouse Square is between 18th and just beyond 19th Street on the south side of Walnut Street. 2104 is two blocks west and also on the south side of Walnut Street. This block is now occupied by a high-ride apartment building.
Angier was 14 years older than Cordie and his left arm had been amputated following a hunting accident. They did not elope but had a major society church wedding and then separated three years later (and divorced three years after that). Angier did not go to Detroit or work in the auto industry. Cordie's brother Tony was also briefly married to Angie's sister, Mary (10 years his senior).
Angie and Cordie were married May 08, 1915, at the Episcopal Church of the Holy Trinity on Rittenhouse Square, two blocks from the Biddle Mansion. Their first of two children, future ambassador Angier Biddle Duke, was born November 30, 1915, 29 weeks and 3 days later (normal human gestation period is 40 weeks).