Hi,
Since Xref don't work with corona I've outsmarted corona :) and use RF_Cache to reference some objets in a scene. And everything would be ok, yet RF_Cache objects are beeing rendered always (no matter what referencef scene may contain) and I use visibility of RF_Cache. Simple as that....
And this is where it gets pretty spooky.... Because invisible objects can be rendered! When You want to investigate and isolate buggy invisible object nothing renders (this is reasonable: DO - render nothing, GET - nothing). This is what i mean:

This effect is similar when You have two meshes overlaying on each other. But one mesh is invisible..... spooky :)