Visible crew/equipment: Waller is telling "Task Force X" about the additional mission they need to pursue, saving Rick Flag. Watch the shot when Bloodsport repeats "Rick Flag?" and Waller replies "I know." The team is going through dense, uninhabited tropical jungle, but in the trees there are people in T-shirts just standing around looking at them. (00:31:50)
Visible crew/equipment: In the club scene when Polka Dot Man is dancing, when the camera spins around you can briefly see the top of a camera/gimbal.
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