While playing I’ve noticed on the maps Oasis, Anubis, Volskaya and Hollywood that the sound gets significantly lower, and/or sound effects (like mousing over a character in the character select screen or voicelines) cut out completely. In addition, shooting sounds and healing sounds do not play at all during the entire match.
I’ve updated sound drivers on my own computer, uninstalled and reinstalled the game, and do not have this problem on any other game or piece of media, so it is not my headphones. I only run into this glitchy sound problem while playing overwatch.