Normal map doesn't work with loaded object.
Only basic 3d Components are effected.
Test was on QDS 1.6.1.
Cylinder is QtQuick 3D basic object
Box was exported from C4D.
Cylinder and Box have same material that imported from c4d.
Sphere was exported from C4D and set new Default material with Normal map.
I also tested fbx object from 3ds max but same result.