That’s weird! But I’d wait to see what comes in the mail from them in the next week and hopefully they don’t ask for the medical exam to be done again! If it’s the marriage cert you should be able to just upload that online but I’d recommend mailing a letter stating that you completed a medical exam in your home country. That’s what I did and they cancelled it 3 weeks later and then 2 weeks later my green card was approved and came in the mail today. I submitted AOS march 10th too!