Wrong Viscous force when using "density variable" in turbulenceProperties

A new "density variable" feature in turbulenceProperties was introduced in v2012. (Release Notes) When I was testing the DTCHullMoving tutorial with "kEpsilon" and "realizableKEpsilon" models and "density variable" in the constant/turbulenceProperites, the viscous component of the forces are too much underpredicted (over 7 times samller compared to the original settings). But the pressure component is almost the same as original result. The results are comparable with the original tutorial when running without "density variable" option. I believe there is a problem with that new feature.