Character mistake: When the MC introduces Lucius and his team during the naval battle, he says, "Today, we relive the battle of Salamis; the Trojans vs the Persians." The battle did involve the Persian empire, but not against "Trojans", but rather the Greeks.
Character mistake: When Jodie and Colt are in her trailer, discussing what should be done next, Jodie suggests Colt needs to cross the border. But they are in Australia, which only borders the sea.
Character mistake: The official in charge of announcing the voting results keeps pronouncing Cardinal Adeyemi's name in different ways; he puts the accent on the last "e" the first time, then the French way on the last "i", then mere seconds later the "e" again. Considering Adeyemi already walked in the conclave as one of the 4 favourites, and that utmost care was put in the preparation of the ceremonial (in an earlier scene, Ralph Fiennes' character makes sure he knows how to pronounce the name of one of the unimportant cardinals), it's quite the egregious mistake that he keeps repeating. (00:44:20 - 00:44:50)