In A New Hope, Darth Vader on Tantiv IV says: “several rebel transmissions were beamed aboard this ship from rebel spies…”.

Except that, in Rogue One, we see that the plans were NOT beamed onto Tantive IV - it was docked inside Mon Calamari flagship, and the plans were physically sneaker-netted through a door from one rebel to another as a data tape - witnessed by Darth Vader!.

Is there an explanation for this discrepancy?