Hello, your fix is really awesome, since it finally let´s us reflect transparent objects/foils or masked objects, like clouds 
(have not tested it with decals so far, but they should work too). however, i stumbled across some problem, when i wanted to reflect the transparent objects in solid metal objects (opaque objects set to metal = 1). I made a video, there you can see it, the transparent objects render black without color, but on closeup the color comes back.
I also noticed, that the new sunsky object, or its exponential height fog covers those transparent objects in the reflections of solid objects. The fog or atmosphere seem to be drawn on top of those transparent reflections and hiding them.