Revealing mistake: Some scenes in the jungle involve heavy downpours of rain, but rain drops are not seen splashing on Mowgli or the jungle creatures.
Revealing mistake: When Apocalypse first introduces himself to Magneto in the factory and tries to persuade him to join his side, a seam in Apocalypse's facial prosthetics next to his mouth is starting to come apart during a close-up shot.
Revealing mistake: When Lockhart slices his cast open, his missing tooth is just cosmetically blackened. (01:47:00)
Revealing mistake: Right after the little girl sprays the monster with bug spray, you can see the costume of the monster, it's wearing a black cap. (01:19:00)
Revealing mistake: In the opening scenes, we see a very pregnant Draka reclining on a bed of animal hides as Durotan watches over her. In the extreme closeup, we see Draka twitch her lips, and her small tusks flex from side-to-side with her lips, instead of remaining firmly aligned with her jaw as they should.
Revealing mistake: The subway station is identified by its internal signs as "Central" station, but as the Suicide Squad enters its exterior entrance, the sign above declares that it is "Bay St." station. Bay Street Station in Toronto is frequently used for movie shoots, as it has a complete lower platform which has been out of service for decades (https://en.wikipedia.org/wiki/Bay_ (TTC) #Lower_Bay).