I just did this a month ago, the cause was a faulty black water fill sensor. I was watching and it didn't seem to fill, well I kept filling. I know, I know. Anyway, we heard a bang and noticed the insulation under the trailer had filled with water.
End result will be determined as dealer is dealing with Jayco wether it is a warranty issue or not because of the faulty sensor.
The trailer is still at the dealer. Damage: the tank separated from the trailer resulting in broke brackets, damage to the insulation, damage to just about everything below the commode. Oh, also it filled the camper floor with maybe an inch of water............We had used the camper twice..........ya.