Originally Posted by Forrest Gump

A byproduct of this however is water condensation near the evaporator. There is generally a drain to get rid of this water. You may have noticed water on the ground when you park your car after running your AC. That is where it comes from. But sometimes the drain becomes partially or completely plugged and the water cannot drain properly.

It is common practice to spray a fungecide in the ducts to kill this bacteria and get rid of that smell. Just beware that it can come back eventually and would need treated again. Whether it should be covered under the bumper to bumper would be debatable but I would push for it since it only has 15k on it. Obviously it is not engineered to be this way.