Water Leak

I have a leak that I can't figure out. The area under the sink, where the low point drains are, is getting wet. In March the trailer went to the dealer to fix this and the low point drain valves and associated fittings were replaced.

This week I noticed again that the fiberglass was wet. I think that the water may be coming in through the city water fitting which is just above the low point drains. I wrapped all the fittings and valves with Kleenex and they don't seem to be leaking. The city water connection is caulked and does not appear to offer any way for water to get past. The connection has a rotating female connector which connects to the male end of the water hose. Do you think there is any way for water to get past this connection and into the wall and down to the fiberglass surrounding the low point drains? By that I mean, not through the caulk and bedding butyl, but rather through the fitting itself. The leak occurs when there is no hose attached.

I did pour some water on the fitting and found moisture after the test. Unfortunately, I didn't feel for moisture before the test. Right now the trailer is 100 miles away so I can't repeat the test.