The Lotus and the Steel - S4-E13
Deliberate mistake: Every native of the Japanese village that Wolverine visits is conveniently fluent in English, and they even speak English to each other when no other people from English-speaking countries are around. (00:04:45 - 00:20:45)
Deliberate mistake: At Pete's diner, the owner puts the tray down, and instantly glasses appear in front of the 5 patrons. (00:02:50)