So, I was doing Due Upon Others, and part of it requires going into a dungeon, where you get the instance quest Late Charges. What happened this time, after talking with Luigi Vandolo, I fought the guards, but it never registered that I did talk with Luigi. After the battle, I had to talk to him again, and fight the guards again. I recall a similar bug with Ricky Ticky Tabby, and I'm not sure if that has been fixed.