Shader Graph BUG ? - No "Position" input in the master node

Hello, i’m using the beta version of Unity ( 2019.3.0b10) and the 7.1 version (i tried both of the versions) of Shader Graph and when i’m using it, i have no more “Position” input on my Unlit Master / PBR Master.
I don’t know if it’s normal or not, i havent saw anything about that on the changelog.
The only thing i have is : Vertex Position, Vertex Normal, Vertex Tangent, Color…

I only created my project with the Universal Render Pipeline and created shaders.

same :<

the docu doesnt know that either.