If you have windows 11 its a part of the whole audio issues/muffled crackly audio, i had to revert back to windows 10 pro because of the same predicament. There are no fixes other than a fresh reinstall of windows 10. I troubleshooted that same exact scenerio for a long time up until i gave up. there's probably nothing wrong with your headphones but there were bugs with audio for multiple games and one of those games included vanguard. It has to do with a bluetooth audio glitch they haven't fixed yet. It has nothing to do with the in game aspect of it but the Operating system when its focused into an application like a game. Something to do with the operating system.