Continuity mistake: When Polka-Dot Man hurts Starro's leg, its minions cry out in pain as well in unison, but they do it holding their knee or thigh in one shot, their ankle/calf in the next. (01:53:00)
Continuity mistake: An personal assistant brings news about the attack on Jotunheim. Suarez turns towards her holding a sheet, but in the previous shot he already threw the document on the desk striking a pensive pose. (01:22:05)
Continuity mistake: The government forces are rounding up the foreigners outside the bar. Bloodsport finishes his beer and puts it down; the bottle is facing opposite directions in the two shots, just look at the label. (01:02:10)
Continuity mistake: Seeing all the Starro drones being held captive in the "Dirty Little Secrets" section, Rick Flag says "Good God". Thinker replies "If God existed..." etc. During this sentence Flag lowers the gun slightly before the first cut, but the gun is angled higher as it cuts to Peter Capaldi and even higher in the wider shot. (01:23:05)
Continuity mistake: When the team gets to the rebel leader's tent unnoticed after a patently absurd massacre, Alice Braga is holding her cup with both hands around it. Reverse shot, and she has one hand on the top and one on the bottom. (00:36:00)
Continuity mistake: Dubois is scrubbing the floor as Amanda Waller exposits to her team of analysts who is he. The rag on top of the alcohol bottle reaches the level of liquid in some shots, not in Waller's semi-POV. (00:16:00)
Continuity mistake: When Harley and not-Milton join the others at the end of the movie, shadow areas appear and disappear between shots (rather obvious when King Shark asks his first "Num-num?"). (02:01:10)
Continuity mistake: When Polka-Dot Man shoots his projectiles at his giant mom, he's standing in the sun or in the shade depending on the camera angle. (01:52:45)
Continuity mistake: When the people in the control room wake up and find out there's "A freakin' Kaiju", the clocks are showing entirely different timezones from the previous instances, with a wild difference from one another (earlier they were a couple hours apart, now we have even 9 hours), and none of which matching the time when the action supposedly takes place (it was late morning, past 10 AM as shown by the surveillance room clock and the phone in the hands of Harley's torturer). (01:46:45)
Continuity mistake: When Flag collapses after his fight with Peacemaker, his hand is off the shower tray. Peacemaker then talks to Ratcatcher 2, and Flag's hand is well on the tray. (01:31:40 - 01:32:05)
Continuity mistake: When Peacemaker sticks the detonator inside the explosive after the humorous argument with King Shark, the detonator is suddenly lower in the last shot. (01:21:45)
Continuity mistake: After killing the guards all around her, Harley rushes into the next room, kicking the door open, and begins fighting in close quarters with more. She breaks the arm of one of the guards who tries to stab her through the bars. In the sequence, the red wrap is covering her fingers in one shot, it's underneath them in the next. (01:12:15)
Continuity mistake: At the beginning of her escape, Harley faces three guards. The rightmost one is smoking a cigarette, then has no cigarette in his mouth, then he has it again. (01:11:25)
Continuity mistake: Ratcatcher 2 tries on some round glasses holding the box with her thumb on the top of the side, into the opening. Wider shots have her hand placed towards the bottom. (00:53:35)
Continuity mistake: El Presidente Luna stops moving and bleeds from his mouth with his palm against the floor. He's wide-eyed dead and motionless, but next time we see him after Harley stops musing over how well-endowed he was, his hand is turned around, palm up. (00:48:35)
Continuity mistake: When the valet tells Harley that the president wants to see her, the guard behind Harley is looking towards her. For her response, he's facing away from her, and her facial expression is different as well. (00:42:00)
Continuity mistake: Bloodsport is talking to his daughter about her crime. During the conversation, the continuity between shot and reverse gets jumpy at times; for instance when he mentions that she "dragged out the paternity test" Idris Elba stretches out his arm only to be still when his daughter screams at him. Later on he reminds her he told her to do 'her thing' and gesticulates with the right hand, but his arm is still and low in the next shot. (00:00:17 - 00:16:50)
Continuity mistake: Amanda Waller told Flag that they cannot retreat from the beach. Harley chirps "Okie dok" as a response; in the first shot she is putting her right hand on the weapon, but in the next she is out of focus in the foreground with the same hand on her earpiece. (00:09:15)
Continuity mistake: Once he reassured the crew about Weasel, Flag orders everyone to get in the position for the paradrop. He motions towards them bringing his hand down, which is operating a switch above him in the next shot. (00:05:55)
Continuity mistake: On the way to the airdrop, Blackguard asks the others "Is this thing a dog?" Next to him, TDK has his hand in his lap to a fist in one angle, palm down on his thigh in the next. (00:05:20)
Answer: It's a combination of various reasons. Will Smith wasn't available to reprise his Deadshot role, so there was a shift in the story. King Shark was intended to be in the first film, but the CGI was too extensive, so they went with Killer Croc. In this film, they took the opportunity to bring in King Shark as the "monster" character. But, this film isn't really a sequel or reboot. Basically, this is a new storyline with new characters, and many of the previous characters are just not in the film, with no exposition on what happened to them, and they may not even be part of this film's "universe." The fact that some of the actors play the same character in both films only serves to muddle the concept of this film not really being a part of the previous film's continuity.
Bishop73