The shadergraph node "texelsize" does not return the correct value when you reduce the texture quality in quality settings. I discovered this while working with the surface gradient framework, where stepsize become mismatched once the texture resolution is reduced in project quality settings (Master texture limit). 

_Documentation has this to say:_
_"The width and height of the texture object report the original, non-limited sizes. You may have to take this into account if you perform special sampling or processing with textures subject to the master limit quality setting, and you use masterTextureLimit > 1."_

We have no way that i know of to access the master texture limit in shadergraph so it is hard for users to compensate (and somewhat obscure to discover that you need to do so)