I had shipped eggs last year (chicken not ducks) that had major saddling like that. I just set them with the big saddled part facing up. My chicks had zero issues hatching and came out healthy. They are 6 and 7 mo old now and starting to lay and all doing great. maybe that isn't the norm for saddled air cells I don't know. I just know I had 2 sets of shipped eggs and some in each had it, a LOT of them not just 1 or 2 and never had an issue because of it. I will post up some pictures of my eggs so you can see. IMO I would try not to worry too much. It looks like it may have internally pipped or is close. just give it time to do its thing.