Mid AC Unit is Not Releasing Condensation Onto the Roof

[mills28]

My 2012 36RE has double rooftop Coleman Mach air conditioner units. The rear unit is releasing condensation in a stream that goes off the side. The middle unit is not showing any condensation release. I had it running all day and nothing pooling around unit and nothing running off.

My question: is there a connection between the middle and rear AC that lets the water run off in one location out the rear unit? I am not seeing any water coming through the ceiling into the interior but that doesn't mean it isn't leaking into the ceiling and making its way down the side and destroying whatever wood it is passing over... I don't see any water dripping down anywhere else but the rear AC. Please help as I know first hand what water damage does to an RV.

[830hvacman]

How is cooling vs the rear unit? Might run it for several hours and check temps of the Return air and Supply air. Then turn it off and swap units - run the other for the same time and check temps.