Material Functions: Default values don't work for scalars

Hi Guys

I have come across an issue and would like to know if this is a bug or just an omission on my part.

I have a material function wich uses Vector3 and scalars as inputs. I defined preview values and checked “Use as default”. This does work for Vector3 inputs but NOT for scalars. For all scalars, I get 0 as the default value, no matter what I set the preview value to.

Any ideas?