john9818a on 2/3/2016 at 17:09
Ok I solved the mystery on this bizaare issue. The missing sounds started as soon as music started playing which required a loudspeaker script from miss16.osm. Once I removed miss16.osm from my mission the problem disappeared. I added the script, tried dropping all scripts and reloading them but the problem persisted as long as miss16 script was loaded.
I ditched the loudspeaker idea and went with ambient hacks on each of the loudspeaker objects.