Hi.
I also have a 2015 passport 2920bh that had a major leak onto the carpet. I sucked out nearly 3 gallons of water after a heavy rain storm over the last summer.
What I found was the rubber seal they glue to cover the slide cable hole was pealing/tearing off from the slide cable bracket smashing it. I glued it back on and sealed it really well. No more leaks, however the cable bracket continued smashing the seal. This seal was on the right side on the bottom cable. I believed the slide was not adjusted properly as this was only seal being damaged.
Camper is at dealer now because of this issue and they are telling me it is adjusted correctly.
Check your cable seals.