When in the Mission Editor, you can make multiple units and list them as playable, thereby enabling you to continue with that unit after your current one dies. However, when you die, that light sad music seems to appear and the gun sounds no longer work. I have tried this both as OPFOR and BLUEFOR with no change.
To sum up, once you die and select another unit, you can no longer hear any weapon being fired.
Make a unit, (Player), make a unit / group (Playable)
Kill unit (Player),
When menu appears select "Team Select"
Select a unit and spawn back into game
No gunshots can now be heard.
This is an issue.
All audio ceases to play after a team switch, save for the ambient background noise (ie. crickets and forest sounds).
Several identical issues have been posted due to this bug:
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0001933
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0000481
0000419
0000271
0000244
0000164 (this one)