I had the same problem when I forgot to open the gray dump valves. Water overflowed from the top of the rank and actual filled up the plastic belly cover and finally poured out on the ground. All the insulation material was soaked and had to be removed.
Call the dealer for an appointment and it would be 2 months before get could get me a date.
Called a smaller RV dealer who had always been receptive to my needs. What he told me is the tanks on my model and many others are not sealed like the dump drains. The waste water pipe slips into a rubber gasket and that us it. Some are tighter than others but the hydrostatic pressure will eventually break the gasket seal and leak.
This dealer says he can seal it but at a cost that I was not going to pay.
Will not forget to open the gray water valve again! Dry camping is my only concern. Will empty my blue boy tank daily!