// Used to lower moiré pattern and self-shadowing shadowCoordinateWdivide.z += 0.0005;
The bias is the small value you add to the vertex's depth in order to (I quote you) lower moiré pattern and self-shadowing
Here it is 0.0005.
What was suggested was probably to try greater values
EDIT : answer to your ... next post : OK, sorry it cannot be so easy to fix !