[Randallw]

Star trek's history is inconsistent because of Temporal incursions. Aliens are changing history so much you can't be sure of anything. Enterprise is hypothesised to be a new timeline because of the temporal war, and in Voyager they have an epsiode warning of the Krenim but when they do meet them they've forgotten what they had learned. This is explicit since the Krenim are actively changing history (I like them so much I am playing them in a game)