Unreal Engine 5.4.4. Just happened to have the same problem. Funnily enough just yesterday I did not have this issue in either 5.3.1 or 5.4.4. Everything happens just like described by everyone in this thread. The only difference I think, is that the sound is coming from the right side of my headphones, which is kinda annoying, but at least with the headphones unplugged there is no audible sound at all.