why if I switch the material in "flat tessellation" mode it start flickering (z fighting)?

When I try to create a material in blueprints and I switch in “flat tessellation” mode it start flickering (z fighting) also without any texture or something, how I can fix that?

Z fighting implies there are two surfaces which exist on the same plane. Tesselation shouldn’t cause this. Can you post a screenshot of your material and the error?