When Aunt Clara drops into the fireplace, a big puff of soot flies all around, however in the next shot no soot shows up on the white fireplace or on the white carpet as Aunt Clara walks to a chair.
During the "If You Like Piña Coladas" montage, Jack's shirt changes when he shows Isabel that her mother turned his hand into a crab claw.
After Jack has been hexed by Aunt Clara, and asked Isabel out on a date, he backs toward his trailer, still talking to her. His bike is directly behind him, and he will trip over it in a second. After a close-up of Isabel, Jack is shown, and only the wheel of the up-ended bike is visible.
When Jack is talking to his ex-wife, Sheila, on set, her shawl is alternately on/off her shoulder between shots.
When Jack and Uncle Arthur are talking at the table making a smoothie, the lid isn't there. However, afterwards the lid is firmly on the smoothie maker.
The movie takes place in Los Angeles, yet Jack complains that his ex-wife "won't sign the divorce papers". In California, your spouse doesn't have to sign anything for you to get a divorce. It is a community property, no-fault divorce state.
When Isabelle is shopping in Bed, Bath & Beyond and is talking to her father, she selects and adds one brand of pizza cutter to her cart but then selects and adds another brand as well.
(at around 1h 35 mins) When Jack and Isabel arrive at their new house, a tree appears in the front yard and their neighbor faints; right after she faints for a brief moment a crew member, the camera and boom mic are visible as a reflection on the glass window.
(at around 45 mins) When Isabel and her father Nigel are sitting down at the table at the coffee bean, the camera is reflected on the toaster from behind the booth.
(at around 45 mins) When Isabel's father waves to her a car drives in front of him and he disappears. As the car goes by the boom mic and camera crane is clearly visible on the car window.
When Maria comes to the door with the Bewitched basket, someone is visible in the mirror as Samantha answers the door.
When Nina, Maria, Aunt Clara and Isabel are having breakfast, they are all sitting around the table and there is a French press coffee pot on the table. When the French press is in close view either the camera or boom mic are clearly visible on the lid of the French press.
It's unclear why Nigel Bigelow would be turned off by the beautiful waitress with hepatitis, since he could cast a spell protecting himself from communicable diseases.
(at around 31 mins) After Aunt Clara fell down the chimney, the boom mic is visible as a shadow behind Isabel and Aunt Clara on the bricks on the fire place and on the curtains.
Jack Wyatt (Will Ferrell) complains that in the original, Darrin was recast and no one noticed. In actual fact, fans were so turned off by the sudden, unexplained replacement of Dick York by Dick Sargent that the show plunged drastically in the ratings and was canceled soon after.
When Maria and Nina are counseling Isabel in her trailer, Maria is holding a plant. As she shifts it from one side of her lap to the other, she accidentally brushes it past Nina's face knocking her bangs into her eyes.