The diocese that you are visiting. The local bishop makes the determination for his own territory.
It isn’t for us to decide that the bishop should have said something different (not that you are, so don’t take that the wrong way). It’s his decision to make; specifically because the Holy See made that determination for this particular part of the Mass (again, see GIRM #43).
While I can say “follow what the local bishop directs” I can’t offer any suggestions on how to learn that, other than to suggest following the directions of the deacon or priest (if they’re given) or simply to follow along with the majority of what everyone else is doing.
This is not really a significant issue. If it were significant, the Holy See would have required more uniformity rather than leave it to the discretion of the local bishop.