As I stated previously, all the data on the objects must match. In the case of refinements, it does not. Simply because you do not see data displayed in item properties, names, tool tips or otherwise, does not mean there isn't variations in data values operating behind the scenes.Kyronix has stated,
And I still refuse to accept that answer, since refinements do not have charges like runic hammers (or other tools). There's no reason they can't be like apples, which weren't stackable at the beginning. I am still waiting as to why two refinements of precisely the same name inexplicably have different properties.
I could go for stackable of the exact type, e.g. scour of defense for gargish stone, as at least helping a little.