Probably an ignorant question, but does DR offer different types of optimization when compiling/saving bsp brushes as seen in the first picture? Most BSP based game engines have optimisation that is intended to reduce the polys etc. for lower performance computers, In the Unreal engine this optimisation usually messes things up with VERY little poly reduction. Anyways I know I have no experience with DR (yet) but an easy fix with the early Unreal engine was to move the offending brush away, rebuild, then move it back and rebuild. Good luck with this guys..