Part 10: Boards for Sindenis
After getting the boards, I was passing by Drannor the Aug Trophy Hunter, and decided to hand in some trophies before I went to continue the Burning Archer quest.
When I spoke with Drannor to get a trophy quest, the Burning Archer quest advanced to part 11, the yew boards were taken and a window appeared with some dialogue from Sindenis, saying thanks etc.
Part 11: (I think) Loot yew treant knots, oastic droplets and fiery dire fangs. In the quest window they were listed in that order.
I got the oastic droplets first, and the quest dialog said something like "you've almost completed your task, only the fangs to go". Not really a bug, but I don't think it was written for those of us who do things out of order.