It is unlikely that your seals are bad as you mentioned that your coach is new. It could be some debris is caught in the lower groove of the valve, and it is not closing fully. It happened to me once. Fortunately, it only takes a few minutes to remove the 4 small bolts and slide out the valve assembly for inspection or cleaning.
When you close the valve, make sure it is closed. It gets tight with about 1/4 of stem showing. It is not closed. The handle needs to be tight against the housing, no stem showing like the valve on the right.