Continuity mistake: During the credits, while the young kids are racing the military car, the jeep behind always has a roof, as seen in all the outside and inside angles. However, in barely half a second, when the cars turn towards the base, the jeep has no roof.
Continuity mistake: Just before Irina enters the warehouse with her men you can see she has no sunglasses on, as she took them off while speaking to Indy, but as she enters the warehouse we see her remove her sunglasses and hand them to one of her men.
Continuity mistake: The CCCP emblem on the back of Irina Spalko's uniform appears and disappears between shots, most notably when she is descending off the cliff and we get a clear view of her back-minus the emblem.
Chosen answer: Because the film had a global release date, and premiered the same day in every country in the world. Obviously, the studio felt this was the best day to do it.
Twotall