I had this bug as well yesterday. The communications worked the first time a played the mission, but DCS crashed mid mission so I had to start over, and every single time after the first playthrough, the communications would not work. But I might have found a solution, easy communications were off for me, but I enabled easy communication then clicked apply, then I went to options again and disabled easy communications straight away. I started the mission and if it wasn't fixed, I restarted the mission and then it worked. As soon as I shut down DCS, the mission would break in the same way, and I had to do this procedure again, I tried it twice, once without VR and once with VR, and got the mission to work both times.