Factual error: Shazam catches the bus with his hands, but it lands on his hands and face by the windshield. This puts the entire weight of the bus being supported by just the front windshield held by Shazam's hands, plus the momentum of it falling from the bridge hitting him. No way the glass could support all that and not break. Especially since it already cracked from just a guy falling on it.
Factual error: When the young Sivana is arguing with his older brother in the car before the crash in 1974, the digital display on the car radio isn't accurate for that timeframe.
Continuity mistake: When Billy drops his notebook into the garbage can in the bathroom, it's open to the final page with his mom's possible addresses on it. But, when the other kid finds it, it's closed.
Other mistake: All the kids at the foster home are of very different ages, but they all go to the same middle school.
Continuity mistake: When the robbers enter the supermarket and start shooting Billy, in the following shots Freddy's distance from Billy changes, appearing closer in close up shots.
Continuity mistake: When the Sivanas' car is landing there is a "blink and you'll miss it" moment where we see the front of the car and its window is flat when it lands but in the next front shot the window has been bent fully forward.