The displacement setup for this material makes no sense.

• Mix Shader and Shader to RGB should not be part of displacement nodes.
• There is no Displacement node used. https://docs.blender.org/manual/en/dev/render/materials/components/displacement.html

"Mix Shader and Shader to RGB should not be part of displacement nodes: "

I can remove mix shader and shader to RGB. and the result is no change. attached screenshots shows the this{F7557884}

"There is no Displacement node used."

displacement nod can't be use in eevee ?  But why it takes  effect when I use it?
The same material is inconsistent on both surfaces is the problem

I add displacement node and solved this problem. thanks!