After Larry and Blondie talk about dogs in China, she runs out and the scene changes to the apartment's patio. There, the shadow of the boom microphone moves onto and off the curtains above the dog in the chair to the left, twice.
The age of an actress or actor playing a screen age may be a matter of opinion to a viewer, but can NEVER be a 'goof' ... it all depends on how they carry it off, of course. Marion Davies did fine here (as did Billie Dove, who didn't get criticized for the same age gap?)
At age 35, Marion Davies was at least ten years too old to be playing a newbie, still virginal, follies girl.