Is drywall that is allowed to get soaked and then gets covered up.
I'm speaking mostly of the drywall used as fire wall in multi-unit buildings.I have seen these walls black with mold and then get covered up with the finish wallboard and there it is in your new house for you and your family to enjoy at no extra cost.
The town I am working in now(suburb of Chgo)will not allow any mold(that the Inspector can"see") to be covered or left untreated.The general contractor pays to have any visible mold washed with bleach and soap and then painted with kilz.
In all the years I have been building in new const(20+)this is a first.
You might want to talk to the Building Dept.and to your insurance agent.Insurance co are rewritting homeowners policies in some states because of the mold issue.Luck