Ok, forget it, it's a bug, but I think I know why. I may not have done it in the order I should have to get the quest, and the quest probably should have been disabled afterwards, but wasn't. Oh well, only had to "End Task" 4 times...
Spoiler-ish
So I just finished it! Best Stalker yet, very cohesive, well planned out, and immersive. Only 3 maps, but they all went together well. Just wish there was more to do in Pripyat. Love the urban setting. Unfortunately, the last 2 games used the urban settings for a massive battle, so it obviously doesn't feel as good.
This had the "best" ending yet, which is disturbing when you think about it. I was actually slightly surprised that it ended when it did. I was expecting another run for the CNPP or a big reveal of what was going on.
Ran the game at 1920x1200 maxed out on an i5 750 and 5770, not a chug except when loading between areas. Aside from the aforementioned bug, nothing big.
Really hope they make another one. Not sure where the story will go. Maybe a Duty/Freedom member one. Just hope they add some more guns... Getting tired of the TAR, TR301, SPSA12 and AK. Will play again...