Other mistake: Mike and Dave put the ad on Craigslist, and people begin to share it through social media. The first time we see someone share it through Facebook the date of the post is "March 19 at 12:38 AM." Moments later there's a zoom in and now the date is still the 19th, still at 12:38 AM, but the month changed to May. (00:12:30)
Other mistake: When Rafe arrives at the new school, principal Dwight has his arms full of items he confiscated when the morning has not even started yet, very specific and obvious rule-breakers like a skate, 2 footballs and a basketball. So did some dudes just start playing ball and shooting hoops in front of the principal at 8 am in the middle of the street? Who are those rebels? There's no trace of rule defiance early in the movie. (00:06:30)
Other mistake: Sloppy animation: In the opening scene, the propeller of one of the Japanese planes stops just as it rolls into its dive.