Revealing mistake: As Lydia talks on the phone Mitch walks into and out again from the kitchen and you can see his shadow fall on the drapes to the right of the dining room table. Later on Cathy goes into the kitchen and right after Mitch sits on the piano stool look closely at her shadow. Though not as prominent as Mitch's it can be seen in the same place for 20 seconds as she waits for her cue to enter the dining room. (00:34:00)????
Continuity mistake: As Lydia cleans off the coffee table and walks out with the tray the green pillow on the left of the couch is at the center of the screen. No one touches it but a few shots later as Melanie brings Cathy back from the bathroom it's been fluffed up with the right corner now being higher than the left. (01:39:15)????