I met up with a friend in game and on the server we play on you are only allowed to use in game voice.
As I got in the car I tried to talk to him and he told me over discord chat that he couldn't hear me. I told him to turn down his SFX but this wasn't the issue.
We stopped the car and got out and tried talking to each other. Our mouths would move but no sound came out for either myself or him. Typing in local chat also didn't work as neither of us could see it (had it turned on in the options).
We drove for about 15m and once we got out and parked the car I tried to speak in game again and it suddenly started working again.