We did an inspection yesterday in an unoccupied 4000sq2 apartment, where we found water stains on a section of some woodflooring, adjecent to a wall which also had water stains. We were told by the seller realtor that it was due to condensation caused by the apartment below, which apparantly keeps their AC unit on all day, causing the unoccupied, humid woodfloor to condense. The wood flooring is a laid a top a plywood sheet, which is laid on the concrete structural flooring. IS THIS POSSIBLE???