Voice channel join sound

Usually everything's okay, but randomly it happens so that the sound that should be played when somebody joins/leaves a voice channel you're currently in does not play. Any ideas on why it happens this way? No streamer mode enabled. It can be so that you speak with someone then somebody joins and you actually hear that notification sound but it may be missing for the next guy.
I tried looking for questions like mine but failed. And i know that i'm not the only one with this notifications behavior.