When Marshall goes through the revolving door into the office building, the sound level from the instruments of the carol players outside remains the same. It doesn't fade until after conversations begin.
When the two crooks get "switched" on the train. It cuts to an exterior showing a train with only 1 engine (F40PH), but when they boarded the train, the power consist was 2 engines (back to back F40PH's), and when the train stops at the station, it again has 2 engines.
When Sam is about to kiss Marshall in Charlie's body, Charlie in Marshall's body quickly comes in , then Sam kisses Marshall in the forehead and leaves a big horizontal mark, then when she says "Goodnight my favorite men", the camera comes back to Marshall and he has a little inclined kiss mark, instead of a big horizontal one.