Having worked at a trailer factory years ago, here is my take, or best guess as to what happened there.
The shop monkey.... oops,,I mean the highly skilled trained technician went to cut out the hole for the vent in the next truss opening.
These holes for the vents are cut out using a router. The guy on the roof hollers ROUTER! to warn others he is about to cut out a hole, so they can be clear to avoid injury. No joke, this is how they do it. He then touches the edge of the router to the roof on an angle and flattens it down, forcing the bit through the roof sheeting. He then runs it around the 14 X 14 framing.
So in his haste, he went to cut the hole on the wrong side of the truss. He moved the router in an arc to find the framing, and found none. Oh 4 letter word he exclaims as he realized his mistake.
He moves the router over to the other side of the truss and cuts the hole out. There, done. Now to hide the hole....
He grabs a staple gun and bangs off a bunch to "fix the cutout attempt. Then he grabs some metal tape, covers up his oops and sends it down the line for roof membrane to be installed. It gets covered up, the foreman doesn't know about it and nobody is any the wiser until years later some poor guy steps on it and thinks he has water damage.....
I can almost guarantee you that's what happened. And things like this are very common.
2007 GMC 3500 dually ext. cab 4X4 LBZ Dmax/Allison - 2007 Pacific Coachworks Tango 306RLSS
RV Rebuild Website - Site launched Aug 22, 2021 - www.rv-rebuild.com