Continuity mistake: Flash is running to power up Superman's ship. In the wide aerial shot when he dives towards the pool (after he went past Cyborg and Aquaman with their backs turned to him) notice Diana with hair in front of both shoulders. A close-up with her and Arthur follows and her left shoulder is clear of hair. (01:12:10)
Continuity mistake: After the underground battle with Steppenwolf when they are finally joined by Aquaman, Wonder Woman sums up the situation with "All he needs now is the Lost Box of Men." Batman replies "If he doesn't already have it" in another shot, where Diana's hair is missing in front of her shoulder. (01:01:15)
Continuity mistake: Clark is thanking Bruce for the house. They both look in the distance at Lois and Martha; there are a couple guys fetching boxes near the carpenter, on both sides of the workbench, but they are nowhere to be seen in the new closer angle. (01:45:55)
Continuity mistake: When Dr. Silas Stone is speaking with Victor, he is wearing a completely different set of clothes from what he was wearing at the lab in the scene just prior. It is implied that the scene happened immediately when coming home from the lab.