Thanks for providing this feedback, while I will certainly be sure to forward this to our Far Cry team for further review, it is unlikely this game will receive any further patches / updates this late in it's release cycle. I understand this may not be the response you were hoping for and apologies for any inconvenience caused, but please keep an eye on our official website, social media outlets and also these forums for any potential news in the future.
HOLY **** GUYS MUSIC PLAYED!
I was well aware of this issue for a while now, and I've started a new playthrough a couple of months back.
I'm in North Kyrat now, I've got 87% completion with 40 hours of playtime, I explore every nook and cranny, loot every chest, read every note, and mostly listen to podcasts while doing so, since I did not expect the ambient music to ever play again.
Well it just did.
It happened at "Stona Kapa Refuge", a place right beneath the Royal Fortress or whatever it's called. (682, 802).
Anyway, as soon as the text of the location appeared, Unfamiliar Paths started playing and I was in awe.
Interestingly enough, after about a minute of the track playing, I encountered a truck full of Royal Guard, but the music did not get interrupted by a combat track (I did dispatch of them quickly with a rocket launcher, but they did notice me and fired a couple of shots before that, so they were officially engaged in combat)
Anyway, whatever is wrong with the music system, the possibility to trigger these tracks is still somehow in the game, but your chances seem to 1 to 40 Hours of playtime :/