Other mistake: Early in the film Sgt Wilkins goes into Inspector Mills' office leaving Thurston dealing with the public at the counter. When Wilkins comes out of the office, exactly the same dialogue is repeated by Thurston and a man making a complaint about dangerous driving .
Other mistake: When Pollyanna and Aunt Polly are trying on clothes, Pollyanna puts on a hat that is flat. Aunt Polly shakes her head and then she approves of another hat that is fuller. At church Pollyanna is wearing the flat hat.