Revealing mistake: Major John "Bucky" Egan is struggling with a German soldier while Major Gale "Buck" Cleven escapes. He holds the soldier's rifle, which is a rubber prop, as it bends during the struggle.
Revealing mistake: When Agatha's apparent nemesis makes her grand entrance, blasting the front door open, the powerless witch gets thrown against the closet door. The face of Kathryn Hahn's stunt double is fully visible before the camera cuts away to show the fall. (00:30:45)
Episode #1.1 - S1-E1
Revealing mistake: The "game" Lily is playing on her iPad is actually a 14-second video downloaded 10/16/2020, as visible from the iOS photo gallery UI bordering the tablet. (00:12:04)