When Peggy is reading the note from Lyndon about his recovery and possible trip to Europe, there are no folds in the paper in close-up. But in the next medium shot, the paper has several folds.
After Peggy is released from prison, there is a montage of Times Square. Many of the shots are flipped/reversed, as the large billboard for Pepsodent toothpaste is backwards, for example.
Some prints of the film must have an error in the printing of scene of Peggy on Broadway showing a Pepsodent sign backwards, but not all prints contain the error: the print shown on TCM in June 2023 shows a forward-reading and correct Pepsodent sign.
Peggy is released in 1925 and she is show standing in bewilderment, near Times Square. In the following montage, a large billboard for Pepsodent toothpaste is visible, albeit backwards, but that billboard wasn't erected until 1930.
At the end of the evening of gambling, it is established that Eleanor owes $15,000. But the next day, initially Bill tells her she owes $13,000. After the pair cross the room, Bill tells her she owes $15,000.