After getting a new connector and putting it all back together...still dripping.
Turns out the elbow, the connector screwed onto, was cracked. No way to see it, I wanted a new one anyway but the dealer said nah the elbow is fine.
And a tip for anyone with this built in panel of valves...don't just leave the valves turned to "winterize" and fill with antifreeze. There are valves and elbows with water in them still.
Turn all configurations and hope pink goes into all of them, because it wont on "winterize"
It was the bottom elbow that does the "power tank fill"
Geezz, if I just had a gravity fill that can actually be used at a campground water fill station, I wouldn't have had this issue. But I guess screwing a hose to the panel is a better idea for filling a water tank.