Other thing: I was in Modoc today and I have given Cornelius his gold watch back. I said it was in the sewer and the quest was completed. The thing is he didn't took the watch. Did someone else encountered this? Did this happened in the 1.02 version?
I had a different problem with this. I gave Cornelius' friend the watch, the quest was marked as completed. Then I talked to Cornelius, and he wanted me to get his watch back. Since the watch is gone now, another watch quest entry in the PipBoy is marked as uncompleted. I think the main problem is that Cornelius' watch quest wasn't taken out of his dialogue tree when the quest was completed differently.