What version are you using?
Triggers are only supposed to activate once, so it sounds like you're experiencing a bug.
Also, do the sounds interrupt when you get far away, or does it only happen if other sounds are played after it (weapon firing, enemy sounds, etc..)
I'm only able to encounter the interrupting audio issue if many other sounds are played after the trigger is activated, so if that's the same issue, it'll be fixed in the next alpha build.