Oh yes, that is really similiar to my experience and i know what you meant with the sound hooks by now.
But 3 things are different.
1. None of these plugins (or similiar) were installed on my server.
2. Just 1 survivor made this sound. Our entire team couldn't hear these sounds, even as we played as survivor.
3. It wasn't one of these music sounds (have listened to all bacteria wave files now). This might be changeable via add-on.
Think you are right, it goes into that direction. Thank you!