Why is my dishwasher leaking in the bottom center of the door?

I have a Whirlpool Dishwasher (model: WDT720PADM0), which leaks directly in the bottom center of the door only during the wash cycle (not during the fill). When I pulled it out to evaluate - it never leaked. I put it back and leveled it off at the door and it leaked again. I'm not sure exactly what to do. I feel what ever it is - is a minor issue to fix. However, I don't know exactly. I couldn't find that this model had a bottom door seal. I could use some suggestions.

Thanks!