For my part i think it is a problem of not refreshed peripheral context during the game execution or direct sound functions poorly implemented in the game
the gap to solve this problem should not be huge.
I tried with several different sound cards (2 different usb headphone, 2 PCI internal sound cards, and 1 screen speakers) and it is always the same problem
the game is not able to change sound card while running. you have to reboot the game to get the sounds back

i have the same problem with ASUS Strix 7.1
if i change the sound device while ARMA3 is running the game souds mute and im forced to reboot the game to get thee sounds back
very annoying during long missions