Deliberate mistake: The security footage of Proteus' escape from the Muir Island Research Facility is merely the same earlier scene played over again. (00:06:50)
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)