Drag-dropping the attached texture into a shader graph causes the following error and does not create a SampleTexture2D Node:

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.ShaderGraph.AbstractMaterialNode.ValidateNode ()

To Reproduce, create a new Shader Graph Shader and drag drop the attached shader into the Shader Graph Editor Window. Note I have also attached the .meta file in order to provide detail on how the texture was imported.

I believe it may have something to do with the fact it is imported as a normal map as drag-dropping it when set to Default works fine.

Repro'd on DX11