Update;: here's what I found.  The problem was/is the spoiler as nearly as can be determined.  It fits so poorly that it can't really be caulked.  The top and bottom fit ok, but the sides don't conform to the roof (or tend to pull away from the roof along the vertical sides).  The resulting gap is really too large to confidently fill with silicone caulk, for it will pull away from the roof.  Apparently, the spoiler is mounted in putty tape, but that does not work well due to the fact that the sides of the spoiler have only three screws, counting the ones at the top and bottom — and it can't be uniformly snugged down against the tape,  The middle screw pulls the middle of the side side down, but a gap emerges above and below it.  And there is nothing for an additional screw to bite into.  I considered using Dicor, but the self leveling would likely run off, and I didn't have access to the Dicor for vertical surfaces.  That might work, but I finally settled on Eternabond tape.  Taped just the sides and top after a thorough cleaning with naptha.  then tested things with lots of water.  Now seems nice and dry.  While I am pleased with the results of the repair, I am more than a little displeased with the fact it was necessary.  In my view, the spoiler installation by Forest River is a total disgrace (and they have to know it), for unless things have changed since 2015, you are going to have a leak!  What's more, properly sealing the spoiler is not a matter of returning it to factory specs, for the factory and the spoiler design are the problem.  Backin15 and Lostagain above tell the story.  This is not a minor issue, for it is clearly factory related and should initiate a recall.  Such leaks can cause major damage in the rPod.  

Ah! Nothing like mysterious leaks, yes? I stepped into my 180 before taking off to the coast last week to find some puddled water on the slide out counter and a bit on the floor nearly under the vent area. Yet a visual check and feeling all around the vent showed no sign or touch of water, hmmmm? Mysterious! Maybe my plan on installing a vent cover may solve this, who knows?

Tibof, I totally agree with you.  The seals should last a long time.  Ours are on year 7,  still looking pristine, and no leaks.  

Could the water be coming in from above? I got on a ladder and had a look at the spoiler, and I was amazed at how poorly it was sealed. The plastic was warped between the screws with several gaps present, and to make things worse there was a hole where a screw was probably inserted, stripped and removed. I am amazed that I haven't had water inside and hoping all is well between the roof and ceiling. I used half a tube of Dicor sealing up the spoiler. 

I had a similar problem in my 179...not a lot of water getting in, but maybe enough to cause problems over time. I remember reading that others have had it too. I got some silicone sealant (probably recommended by someone on this site) and sealed around the back window and seams on the roof in back...anywhere I thought could possibly be allowing water to leak in. I didn't do anything inside the trailer. The problem appears to be solved, at least so far. I'd try sealing those outside seams before doing anything too extreme. Good luck!