Continuity mistake: When they finally arrive at the bottom of the sewer, Eddie's bandage is on a different cheek. (01:59:00)
Character mistake: Selena Gomez drives into town in a fully restored 1967 Pontiac Le Mans, which is a long box shaped car. However, when confronted with Bill Murray and Adam Driver, Adam Driver complements her on her 1968 Pontiac Le Mans, which is a completely redesigned shorter curved body style. The two look nothing alike.
Other mistake: The type of gas pump Danny used when gassing up the car requires the lever be moved from the on to off position before the hose can be placed back into the pump. It is already in the off position before he finishes.
Revealing mistake: When the Hårgas begin eating their meal after Dani is crowned May Queen, there is a shot of Dani just after the Hårgas pick up their knives and forks where she is looking over at Christian. Sitting next to her is a woman who cuts her food with a knife and fork, raises the fork to her mouth and takes a bite, but there is no food on the fork. She is just miming the actions. (02:13:15)
Continuity mistake: The IV bag has the name of Louie at first but then changes into something unidentifiable and then back to Louie again.
Continuity mistake: After Brandon finds out he arrived in the alien craft, he walks outside in the rain where he finally translates "Take The World" as his purpose. He continues on to Caitlyn's house to tell her what he has discovered and to give her a flower. When he arrives in her room, he is completely dry.
Continuity mistake: According to the countdown, Jordan has less time to live (about 3 minutes) than Quinn, which makes the whole end with the morphine pointless. (01:09:00)
Continuity mistake: After the kids are told Sara hung herself at the hospital, Chuck asks "what are they waiting for, let's go". Stella is bending down to pick up the book in one shot, but the angle cuts while Chuck is still saying the word "go" and suddenly he has vanished from the room as the other two start to leave.
Other mistake: The movie is said to be set one year after receiving Annabelle, but the music box from The Conjuring is on the shelf. Judy in The Conjuring is an 8, possibly 9 year old whereas in this film she celebrates her 10th birthday. If Annabelle Comes Home" is only 1 year after obtaining the doll (2 years prior to The Conjuring timeline) then Judy would not be turning 10 years old; she essentially lost a few years of life rather than vice versa.
Continuity mistake: Dr. Stone mentions there is an emergency exit below the landing pad. He then asks the pilot if there is a camera underneath. In this shot, the pilot has his eyes partly closed and his lips pursed together. It cuts to a close up of him and suddenly his expression is different, with his eyes wider open and his mouth open. (00:19:50)
Other mistake: While in the pool room, Zoey falls off the wall onto a portion of floor that hasn't collapsed yet and loses consciousness. This area is next to the section of floor that collapsed first. Jason jumps down to help Zoey. As he is helping her up, and onto the wall, that section of floor collapses, forcing him to grab the wall to avoid falling 20-ish stories with the floor. As he looks down drop, the section of floor that fell first is amazingly back intact. (00:59:20)
Factual error: She fires the entire magazine of a Glock into the alligator's mouth. When it is empty, rather than the slide locking back and the trigger freezing, there is an audible click every time she pulls the trigger. This could not happen.