After taking back Nelson from Legion, according to PipBoy i need to go back to Polati and tell him about our succes. But he doesn't have any dialog option about our victory...

I am having the same problem, tried finished the quest within the console (GetQuestCompeted/GetQC/Stage ## QuestID commands) but didn't seem to work. Now I'm stuck with the unfinished quest. By the way the is called "Restoring Hope".

I have the same problem.

http://www.gamesas.com/index.php?/topic/1127509-restoring-hope-broken/

Same here. The guy won't recognize the mission as complete (even though everyone's talking about the great victory) arghh...

I also can't proceed with the Van Graf missions. I'm supposed to talk to a guy (B-something) and while he's indicated to be inside the house he's nowhere to be found. He's also not on the second level.

I had a similar problem with Hildern in the You Can Depend On Me quest. The marker kept indicating him to be at a location where there was noone around. I checked there twice at different (in-game) times of the day. Third time the marker led me to a slightly different location in the same building and voila, there he was. I was then able to continue with the quest.

I'm quite disappointed by the number of bugs in this game.

Since we have already seen (well, I have seen) creatures and people disappearing underground, kind of sinking into the terrain if you like, I can only conclude that the guy is probably 6 feet under, buried alive. Prolly just hanging there.

If only we could summon them via the console that would be of serious help.

Happens to radscorpions all the time. Can't recall seeing it happen to people though.