Ambient Audio seems to completely cut off unless I trigger an effect like opening/closing a door. It will then slowly die back down until it is silent again. While rain is going it audio seems to stay on until I go into a building, and then it will go silent again.
This issue did not start until after I purchased the Livonia DLC and loaded it into one of those maps servers (not sure if it's related because correlation doesn't mean causation, but figured it might help?) The audio issue did carry back over to the main map.