Porch roof started leaking about 3 weeks ago. Finally dried out some and think I found the issue. What I call J track, aluminum strip that is screwed around top of trailer like a hatband is what attaches the galvalume roof to the walls. It's maybe 2" wide top-to-bottom, 3/16" thick. It's an extrusion. When viewed from end has a J attached to one side. That J is supposed to serve as a gutter of sorts. The J is maybe 1/2 inch x 1/2 inch. If I was doing this over, would have removed the section above the porch and replaced with something? What is happening is rain is getting past where the original porch roof builder "plugged" the J track so water couldn't flow into/under the porch.
If I hadn't gotten super dizzy (vertigo) right at the time the actual roofing was being installed, like to think I would have seen the issue. Maybe grind/clean the J out good and clean and fill it with fiberglass? Something permanent. I'll add a picture of the hackery that was done before I moved in here.