Blender 2.82

if smooth shading is added to the model smooth shading is removed when adding a bump node with height connected to large scale noise in the normal

Exact steps for others to reproduce the error
1 add a low-poly sphere
2 shade it smooth
3 Go to the shader editor
4 add a noise texture and increase the scale to something like 10000
5 add a bump node
6 connect the height to the fac of the noise.
7 connect it to the normal in the principled shader.
8 render it.
and the shading will be flat.

here is the render:

exsample.blend file: