Can a defective studor vent cause water to leak from the waste pipe when the dishwasher is operated.

We had an addition put on that moved the kitchen 10 feet out 7 yrs ago. Recently I noticed that the engineered wood in front of the dishwasher turned black. Plumber and diswasher repair guy said it is not the dishwasher or the pipe connecting the dishwasher. A leak detection guy came out and tested the water pipes and did not find any leals or loss of pressure. We cut through the subflood under the dishwasher and found a puddle that was on the cement slab between joists and under the sprayed in insulation. No one can figure out how the engineered wood got damp as it is above the subflooring, plastic vapor sheet, and 1/8 inch cork underlaying the engineered wood. Ever heard of such a problem?

Dave

Herndon, VA