Factual error: Johnny's dad and gang come to over protection services to Moon and the singers. Despite almost no time having passed since the first Sing movie, as evidenced by Rosita's children having not aged, the gang appear to have been released from prison. The gang were in for armed robbery and at least one case of escaping prison. The minimum terms for those charges would keep them in prison for years.
Factual error: Steve Trevor tells Aquaman that he is a Colonel in the US Army. But he is wearing First Lieutenant bars on his uniform.
Factual error: During the escape from the farmers market a red London bus is in the background. Those busses aren't used in Gloucester.
Factual error: All Arabic texts in the film suffer from wrong directional rendering. Arabic is a right-to-left language. Its letters have different joined and disjoined forms. The film, however, has rendered Arabic texts from left to right in disjoined letters. These texts aren't semantically wrong, though. For example, deciphering the Arabic message at 0:40:45 point gives "أليس "التنين فنان؟ Translation: "Isn't the Dragon an artist?" The film has even adopted a good font for them.