Mine was the same when I installed my headers. You pushed the back too far down, pull it back up from the rear header and it should sit in the middle better.

When I did mine (used) I had to put the crossover into the front header and get it nice and snug and then put the front header on with the crossover attached. Not gonna lie, it was a booger, but a little bit of convincing and it all went together. Otherwise I couldn't get rid of the gap and had a exhaust leak there.