When Lil goes to Charlie's penthouse in New York and the butler announces her arrival, Charlie stands up from his chair holding a book in his right hand. In the next shot, where he finishes standing, the book is gone.
(at around 17 mins) When Sally is removing her pajamas to give back to Lillian, the camera constantly is moving to keep the nudity out of the frame. However, when Sally removes her top and hands it to Lillian, it can be seen for a half second that Jean Harlow's right breast is covered by a flesh-covered, strapless half-bra that conceals only the lower breast.
When Lillian and Sally exit the soda fountain and walk down the street, the camera dolly grip can be seen reflected in the store windows, bent over and pushing the camera dolly down the street.