Which is rather weird no? Remember when Nicole Kidman was photographed by Demarchelier for the cover, but by Lindbergh for the editorial? So it means they have time to do reshoots for covers. So if Leibovitz didn't have the perfect cover shot, Testino or someone else could've filled up the gap easily.
So now, I wonder, what might've happened? The main cover must have been pulled at the very last minute for this to end up as the cover. Seeing the full photograph screams last minute in all honesty.