The Principled BSDF node has the socket inputs named Normal, with python I checked the values are set to (0, 0, 0)
To check I did:
>>> bsdf = C.object.active_material.node_tree.nodes['Principled BSDF']
>>> print(bsdf.inputs['Normal'].default_value[:])
>>> (0.0, 0.0, 0.0)
If I connect a "Reroute" socket nothing happens.
However, if I connect a group node with values of 0,0,0 the normal seems to mess everything up.
Does anyone have any idea why and how to fix it with right default_value?
This is the Example:
Note This problem only happens with Eevee and not in Cycles.