Yes, I had already visited the dragon in the saved game I was using to test. So I tried with a game in which I hadn't visited the dragon yet. However, I didn't manage to test with this game. Using the console to travel directly to the dragon's lair crashes the game. I tried travelling to the temple ruins and going to the dragon's lair from there, but that also crashes the game, I guess the game must expect you to have completed all the previous steps in the quest before.
Since testing with the shadow dragon proved so complicated, I tried modifying the mod and giving the sword to the otyugh in Irenicus' dungeon instead. There are three otyughs in the game, so I gave the sword to all of them because I don't know which one is Irenicus'. The result is the same, the otyugh doesn't have the sword. Checking in NI, though, the otyughs do have the sword. However, when I try to open the sword item in NI I get an error: "Error reading null", "null". I attach the modified mod.
mymod.zip 956.03K 267 downloads