Here's exactly what happend to me, but it was the "Dead Marshes" that Glitch:
This is taken from the official Xbox360 forum, when the game was first released a lot of players add the same problem:
" Hi all, in my Tracking Hobbits level, I ran into a glitch where the count of Treasures found went to 4/3. After the level, when it was counting my studs, etc., it updated this to 0/3 even though I have found them all and they are in my inventory.
My questions are:
1. Has anyone else run into this and did it impact the 100% completion at the end?
2. If I redo the level, would it count it up correctly and set it back to 3/3? I've been afraid to replay it thinking that maybe it has a "3" stored behind the scenes somewhere and if I do it again it will reset to "0".
Thanks in advance for the help. "
You can read all about it here: Xbox forum link
Is steam coming out with a similar patch for this release?