Factual error: Throughout the film, most Japanese words are spelled in Katakana. In real-life Japanese, however, Katakana is exclusively used for foreign words adopted into Japanese language, like 'table', 'television' (mostly it is abbreviated to 'telebi') and 'racing car'. But in the film, even indiginous Japanese words such as 'samurai' are spelled in Katakana, not - as they should be - in Hiragana (the syllable system used for native words).
Revealing mistake: During the final race, Wrangler is shown knocking a yellow car off the race course. A few seconds before this, there are two shots from behind Wrangler, that are just still frames. The shot does not show Wrangler driving or even moving and is completely still. The shot from behind is merely just a still image, that has been extended to last a split second. The same still frame image is also repeated two shots later. (00:27:35)
Continuity mistake: During the tavern brawl, a group of three henchmen charges at Korgoth. During this parallel montage, the middle man changes from their first shot to their second (where he looks more like Hargon) and then back for the rest. (Also, the masked attacker on the right appears in two groups, but technically it could be twins or there could be more of them.)
Continuity mistake: After Stark fights with the Wakandians his armour is damaged, but while he is drinking on the ship the damage is repaired, then the suit is broken back again.
Factual error: The drum kit that Courtney plays at the concert is wrong. It has too many cymbals, two bass drums (one is unneeded) and she didn't kick the pedals to play the bass drum and cymbals.