Hi Garyosavan,
The assets are set up to be used in a renderer which supports the MDL format, such as Iray.
In those materials the normal does not exist in the sbsar, which is why it does not appear in the 3D preview.
However, if you want to use those materials in real time it is possible to put the normal back in the sbsar, a parameter has been created for this (Cataphote In Normal). You just have to put it from 0 to 1.
You can see where this is in the attached screenshot, in Substance Player.
It is actually the material with the normal visible in the 3D preview which has a bug as this parameter should not be on by default.
I hope this answered your question!