(at around 1h) We see a piece of paper that reads "Wednesday, July 10th 1929", then a few minutes later we see an invitation to an affair that reads "Monday, July 12th 1929". Actually, the 10th did fall on Wednesday that year, but the 12th fell on the following Friday.
When Janet Gaynor go back to New York, crying, she forgot El Brendon's character's name and said twice "Oh El", instead of "Oh Eric"