Corrected entry: Candlestick telephones and others of similar vintage are repeatedly shown ringing (and Christine is shown using two different models of telephone in her house when it would have been unlikely that she would have had more than one). Telephones of this period did not contain ringers. Rather, the ringer was inside a large box which was usually attached to the wall behind the telephone. Such a box is not seen in any shot during which a telephone is shown ringing.
Corrected entry: Reverend Briegleb broadcasts a radio show from the pulpit. Shots alternate between him speaking in the church and the transmission being heard on the radio, suggesting it is a live programme and therefore not being edited. In the shots in the church, there is substantial echo. When we hear the transmission on the radio, there is no echo to be heard.
Corrected entry: Street scenes set in 1928 show numerous cars which were not manufactured until the early 1930s. Indeed, many of the same cars appear in street scenes set in 1935.
Corrected entry: Towards the end of the movie, Gordon Northcott is referred to as a "serial killer." This term was not coined and put into usage until the 1970's. From Wikipedia, it's "commonly attributed to former FBI Special Agent Robert Ressler in the 1970s. Serial killer entered the popular vernacular largely in part to the widely publicized crimes of Ted Bundy and David Berkowitz in the middle years of that decade."
Corrected entry: When Gustav Briegleb confronts J.J. Jones demanding to know where she was, he states that her 'neighbours' saw her being taken away. In fact, she was taken to the asylum from the police station, not her home.