This is an issue for multiple people, both creepside in the 'moors as well as in the non PvMP world--the game music is muting when you log in or zone. Fixing it just requires a miniscule switch of the music slider, but this needs to be done every time! I'm not seeing this in the Known Issues yet, and I know folks on Landroval have /bugged it (myself included), so--is this working as intended? I can't imagine it is.
I've also experienced (and /bugged) as have others issues with ambient sounds following one between zones and even between PvE and creepside in the Moors--again, not in known issue. Just wondering...