I have tried this and my 1st character alone still has no sound effects
I don't know if this helps but I've noticed that changing my game settings(especially resolution) and alt + tabbing seem to exasperate that sound bug. If I get my settings where I want them, then go out to character select and avoid alt + tab I seem to get the bug much less often.
P.S. Verdant Is there a way to force the game client to run in borderless window mode? I found a thread talking about it and it looks like, at least then(5 years ago), it wasn't possible without a third party application?