I was coming on here to ask the same thing. My son’s app was downloaded 8/29. His “other” recommender has not yet submitted a recommendation letter so I wonder if they wait until they have all your materials 
I didn’t know if my son should reach out to ask or just keep waiting. This is our first time having a student apply to Duke. He submitted his application early but is applying regular decision. Any insight from former students that applied last cycle?