Henry the Master Huntsman - marker is in the corner of the map

This quest remained in my journal after Talmberg was taken so I thought it is possible to finish it once Talmberg is liberated. But the quest marker is in inaccessible south-east corner of the map and there is nobody in Talmberg to turn in the quest.
So I hunted all those deer and hares for nothing?

they did warn you that some of the quests would be inaccessible after Vranik

No, unfortunately, not. I don’t really know why it happened to you this way. When I did the same during my first playthrough the game just reported me that the quest had been failed and I could do nothing to restart it. It is not meant to be played after the siege, although I don’t really see the reason why.

Because the castle is screwed so last thing on there mind is what they can get you to hunt

I had same bug, after few in game days it appeared on right spot. Quest giver is in north western corner of Talmberg village. He is tanner and his woman is merchant, she has small shack in front of their estate.