kisslicertalk.com

I was thinking if it's a bug at all, but finally tested out that "Z-GAP" SHOULD work for all structures of support in the model. Currently it does not (there is one critical exception - illustrated below) that unfortunately kills printing of models that otherwise could have been printed easily..
("kills"=it leaves one support layer that is welded to object and practically unremoveable and by this changes the dimensions of printed object).