Shader Properties gone everytime i put specular/Roughness map to Standart Shaders

Hi, just straight to my question. i don't know why my shader properties just gone everytime i put something to specular map.
interestingly, I can copy old material file that already has the specular map assigned, there is no problem appear if i do this steps. the problem only occur to a new material created.
here is the error warnings 
can anybody help? is this bug? im currently using Unity 2017.4.17
 
                 
                before-and-after.png 
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                error.jpg 
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