This sounds very similar to another recent thread! one discovery i made whilst sorting out my gamut settings is that LR edits ONLY in Prophoto (as far i can tell im still googling to see if its changable)and so ive set all my other stuff to do the same. and when i output i do so accordingly...It will be interesting to see if Adobe are using a flash in the pan gamut.
My reasoning for doing this is that it makes sense to me to not keep switching gamuts, and as LR seems fixed to Prophoto then thats what ill in PS as well and the output in whatever is appropriate.