Joxer's underwear displays colorful patterns and trademarks which are only possible with 20th-century manufacture. This is a joke.
Autolycus has an obvious fighting double in the climax. He appears to be wearing a floppy wig which doesn't quite fit.
The introduction of Cleopatra adds further muddle to the series' already-confused chronology, which has had Xena fight in both the Trojan War (c. 1184 BC) and Boudicca's Revolt (c. AD 61). To be fair, the historical Cleopatra knew Gaio Giulio Cesare, who has also met Xena.