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.