I have the same problem in a 6341dk. Right by the passenger side rear slide out next to fridge. I have check all the pluming and slide out seals and no leaks detected. I thought possible condensation from fridge but nothing. Doesn't seem to be getting worse but before i commit to ripping floor up i would be interested to hear what you find. I noticed your model has the full slide on driver side according to brochure.