I actually have a mold addendum attached to my leases ( we are in Florida) rhatvsoekks out that they are to keep things clean, report water problems immediately and run the ac to avoid moisture build up

Invest on a moisture sensor for the A/C system which automatically turns off the A/C when water accumulates on the bottom of the condenser.

If the air is to dry and or to much moisture and doesn't circulate properly then a lot of problems can happen even with no water leaks.

It helps keep moisture from coming up through the concrete and into your basement.

We were told by the inspector that it was a moisture issue but we put in insulation and moisture barrier and a dehumidifier after closing and still the hump remains.

I have also heard conflicting directions on how to insulate the basement to deal with moisture which has been confusing.

Moisture is usually the biggest problem esp in high humidity. 

If so, the cavities behind it will hold moisture long enough to allow mold to form.

In addition to the owner-occupant requirement, FHA is fairly strict regarding condition of the home, like must have working oven, flooring issues, age of roof, no moisture problems on door frames, window sills, etc.  

It's not uncommon, if there is a poor seal around the pipe, for moisture or water to run down the pipe to lower levels of the house.