We had something similar to this in our 38FL shortly after taking delivery. I ended up re-caulking the door frame for the sliding door both inside and outside. I eventually cured it, after several attempts, by pulling out the old sealant from the interior corners at the bottom of the sliding door frame (actually in the runners for the doors) and re-sealing them.
We'd also re-sealed the drain after a few months because I found a small amount of water leaking out after I'd gone in to the inspection door looking for something else.
I had also found a hairline crack in the corner of the shower floor - apparently a frequent problem with the CC showers caused when they are installed (according to the dealer). FR paid for that to be heat treated by a specialist company who work with fibreglass. Now, looking at it, you would never know the crack had been there.
Richard & Diane
2014 Cedar Creek 38FL
2016 F350 Lariat CC DRW
Retired Metropolitan Police (UK)