Audio problem: When they are putting the Cook's body on the sofa, Wadsworth walks by in the background and says "Careful, don't get blood on the sofa" however his mouth doesn't move.
Audio problem: In the scene where everyone gangs up on Mr. Boddy, the audio doesn't match much of the action going on. (00:23:10)
Audio problem: In the third ending, when Wadsworth reveals his true identity, Professor Plum says, "Oh shucks." This sounds like it's been dubbed, and when watching his lips, he actually says something that starts with 'sh', but doesn't end with 'ucks'.
Audio problem: In the scene in the study where the cast gangs up on Mr. Boddy (when he and Colonel Mustard get into a fight), right when Mrs. White knees him in the groin you hear a lot of commotion from the other guests in the background. Included in this is Yvette saying "Oh no it's." (we know it is Yvette because of the distinct french accent) when in fact, she is in the billiard room recording the conversation.
Audio problem: In the first ending, when it's revealed Miss Scarlet murdered four of the six people in Hill House, Colonel Mustard tells Miss Scarlet he has no more money when she wants to blackmail the guests. The other guests reply that they don't have any money either, but look closely at Professor Plum. Although Plum answers "Nor I" to Miss Scarlet, his lips are closed and don't move.
Audio problem: During the re-enactment, at the point when Wadsworth slaps Mrs. Peacock, the slap doesn't touch her, but you still hear it and she still reacts. (01:07:55)
Audio problem: When Yvette shows everyone the open cupboard and the door bell rings, Professor Plum turns his head before the door bell even rings. (00:54:00)
Answer: Yes, the accent was fake. She wasn't a French maid, she was a prostitute who used to work for Miss Scarlett. She was hired by Mr. Boddy.