Using the chisel mod block variation on the framed drawers, and possibly vinnila blocks, creates a dark area in the middle of the drawer.

Light behaves strange with chiseled framed drawers/trims but with other chiseled covers too (i.e. Thermal Dynamics pipe covers). I'd recommend to also open an issue with Chisel mod if not done yet.
But Chisel is still in alpha state for MC 1.1x.x.