I had two Minutemen quests like "Ghoul problem in Sanctuary Hills...." almost complete, having killed all enemies, talked to the settlers and having only to talk to the guy in Sancturary. This approach was reported in this forum as a way of having control over the flood of timed Minutement quests.
Well, as I was clearing some Raiders later on, I got a message that I had failed on of them and when I checked my quest list, both have disappeared. Has antone else seen such a pattern?