You must have confused it. I'm telling you it doesn't give weapon and it never did.
I wanted the entire shisui set on my RDM when I was first leveling it and this was at launch just like you. Not in any higher patch increment. I had full set and had collected some when I leveled my healer so by the 4th run of Shisui I had the full set except weapon cause the chest never dropped it. I was not given a weapon at the end when boss was killed.
This same scenario also happened for BLM which shared all the gear from RDM and I kept it all from leveling RDM. Full set from all leveling dungeons except Abania.
Never got a weapon from Shisui, Bardam, or Doma even though I already had full set immediately upon starting to use those dungeons to level. That's running each one of those 5 times each at least wearing the full set each time and never got the weapon unless it dropped from a chest. I think two out of three of those didn't ever get those weapons because the chest refused to drop it.
Explain?