Continuity mistake: When Cassie meets Santiago, she is grabbing her notebook with her left hand. A shot later, she is pressing it against her breast.
Continuity mistake: In the diner, after the waitress hands the menus, Mattie drops her backpack twice.
Continuity mistake: After surviving from drowning in the river, Cassandra has a blanket over her back. The blanket is covering her forearm or not, depending on the shot.
Continuity mistake: When Ben asks Cassandra to take her oxygen, his hair is messy. A shot later, it's nicely brushed.
Continuity mistake: When Cassandra is checking stuff inside a luggage, her ponytail is either falling over her chest or not, depending on the shot.
Continuity mistake: Ben tosses a fortune cookie at Cassandra, and aims at grabbing his oyster pail. An instant cut later from a different angle, the pail is already in his hands.
Continuity mistake: At the hospital, the nurse that holds the clip folder has both hands apart or together, depending on the shot.
Continuity mistake: At the hospital, Cassandra is talking to a nurse when a kid shows a drawing he made. Right then, an Afro-American man suddenly walks by out of nowhere.
Continuity mistake: At the hospital, Cassandra is cleaning the top of the soda can with the palm of her hand. An instant cut later, she is opening it.
Continuity mistake: When the skater girl stops in front of the ambulance, there's no car ten meters behind her. Half a second later, a car suddenly appears behind her. Also, the cab is further away, the pillar vanishes and a black parked car appears.
Factual error: The ambulance drives by a Blockbuster with posters for the movie Big Fish. Madame Web is set in the Spring-Summer of 2003 (judging by the trees), but Big Fish premiered in December 2023 and the VHS came out in April 2024.
Continuity mistake: Constance's baby's right arm is uncovered except for the final shot where the shroud is suddenly covering him.
Continuity mistake: When Constance gives birth, a strand of hair on her forehead appears and disappears randomly between shots.
Revealing mistake: When Constance's baby is taken out of the water, she is an obvious doll who doesn't wink or move a single inch. She even cries, but her mouth doesn't move. In some shots, she is replaced by a real baby.
Continuity mistake: The position of the hands on Constance's baby keep changing all the time.
Continuity mistake: When Ezekiel takes the jar from Constance, his index finger is below the top. From the opposite angle, it stands out.
Continuity mistake: When Ezekiel points the gun at Constance, he holds the gun with one or two hands depending on the shot. This swaps back and forth.
Continuity mistake: Constance takes the umbrella away from Ezekiel by grabbing the shaft. An instant cut later, she is grabbing the handle.
Continuity mistake: When the movie begins, the way Ezekiel holds the umbrella handle (higher or lower) changes between shots.
Continuity mistake: After Constance tells Ezekiel that "spiders supercharge their cellular structure," the camera strap over her elbow moves upwards towards her neck. This changes back and forth all the time.