Assassin's Creed 3 Ambient Music Bug?

I believe there is an issue with ambient/background music in AC3. The problem is that is non-existent. Unless you playing a scripted event or get caught up in open conflict, the world is remarkably quiet. You hear only the NPC characters and their looped comments. Considering AC franchise in the past has had such incredible music I find it hard to believe that this is an intentional decision. Rather, it is most probably a bug. There is a very healthy thread on Ubisoft's forums regarding this issue, and though it's been raised and brought to their attention, no-one from Ubisoft seems bothered to confirm whether this is a bug or not. If there is anyone here that is able to shed light on this issue please do. I am really enjoying the game but every ten minutes or so I get pulled out of the immersion simply because the lack of ambient music is so jarring.