In the early scene at the piano where Georgy's father has brought her a dress to wear to a birthday party, she's wearing glasses when he starts to say, "Oh, please yourself," but not wearing them before he finishes the line.
When Meredith returns home after playing in the orchestra and sits in the chair talking, the violin case goes from right side up to upside down several times.
In the "Mistress Contract" scene, James tries to kiss Georgy and knocks her glasses down on her face - far enough so that her mouth is seen through the lenses. From the reverse angle, they are properly on her face, and he has to pull them off to kiss her.
The last shot of the movie is extended by reversing the film back and forward.