PS4 Party chat

[Sweetcyn910]

My son has been having a problem the last few weeks whenever he plays a game they use party chat with his friends let’s say there are three friends sometimes he can hear two of them and not the other one. Then he can hear the other one and then he can’t hear the other two. It was working fine before and it just started happening out of nowhere. We’ve tried three different headphones and still the same thing. My boyfriend plays call of duty with his friends a used regular chat and it works fine for him. What could it be?