Well I'm going to answer my own question. I didn't realize there was a check valve built into the hose connection as my older rv didn't have this type of attachment. I punched out the obviously leaking valve and added a new one on the back side of the inlet. The happy part was the connection was nice and open inside my bathroom sink cabinet making it easy to get to.
Now, as to why the dealer just cheaply capped the connection with a dummy plug vs replacing the check valve.... no idea.
One more fun fix off my list.
Scott