Hopefully all of it, as it is a film that has long overstayed it's welcome.So how would YOU explain the difference, then?
TWOK, for example, says 1996. If that's no longer true...then how much ELSE in the film isn't?
Honestly, I wouldn't. Accepting inconsistencies is pretty much par for the course in my Trek life. Even studying history has taught me that. If pressed, I would say that people got dates wrong. Which, believe it or not, happens to people.