I have a 2014 Honda Odyssey with 6000 plus miles on it. This morning I experienced a double clunking when accelerating from 0 to about 14 mph. It felt like I was going over a speed bump. I see from other postings other folks have had the same problem at about the same mileage.
As others have pointed out, start documenting, in detail. That includes what you tell the dealer. If I've read correctly, there may be a firmware update to help with the problem, but some Honda dealers can be too lazy, so push.