Under Extrution by Dual Nozzle?

Hi, when I print with my H2D, I get a perfect first layer, etc., when I print with a dual nozzle. But when I print with a dual nozzle, I have issues with the bottom and top layers under Extrusion. I’ve read that this is a bug, and the slicer suggested setting the wall thickness to 0 and then to the desired number, but that doesn’t seem to work for me.

Kind regards, Keiko