I have had the same experience with my 2008 25 FBSE.
As I previously posted, the rear floors of my 25 FB were soaking wet with the underfloor foil bubblewrap insulation trapping the water there.
The rear bumper trim had no caulking at all and there was free entry of water through the Starboard rear taillight assembly. I also found water coming in through the rear & front window wells.
After pulling up the vinyl & removing the belly sheet metal, I let things dry out for a few days.
I ordered some Rot doctor (Cold Penetrating Epoxy Sealant) & treated the floors liberally.
In anticipation of mounting foam insulation under the floor, I wanted something to keep the insulation away from direct contact with the wood. I did not have redwood available to me & wanted to use something inert. I found some vinyl outdoor lattice trim & used this as spacers:
I then screwed the foam/foil insulation to the floor with the spacers keeping them from contact with the wood.
The bumper & all the belly band trim was caulked with liberal amounts of Sikaflex & reapplied with Dum-Dum caulk beneath the trim as well.
Time will tell I guess but I am hopeful that the leaks are fixed.
I will post a few pictures of my modifications to the window wells in a separate post. (I opted to install drains as I was not confident I could totally prevent the windows weeping water while underway or when in heavy rain storms.)