2.8 Cycles + Alpha channel Problem

Recently I found a problem. I am using RGBA texture for my custom material. Red - AO Green - Roughness Blue - Height Alpha - Metalness Eevee works fine, but in Cycles Alpha channel influence all other channels and I have a messy result. Is there any secret feature that I miss? blenderartists.org/uploads/default/original/4X/0/0/6/006cd6d2a58e5cea9b108d258af4c071a2b2b1b1.jpeg blenderartists.org/uploads/default/original/4X/1/c/7/1c7841aae5c134880dbefba26da757aca7ee2a88.jpeg