Most bolt lugs will always look like that. The reason is the generous clearance around the bolt body raceway. When you close the bolt, it is almost always slightly cocked to one side when you start to turn the bolt down. Being slightly cocked to one side, one lug will contact the closing ramp before the other one.
When the first lug contacts, it acts like pivot point until the other lug catches up. That's the reason for an irregular contact pattern. Believe me, when you pull the trigger, both lugs will get the same pressure.