Sound effects (most notably the zombie shrieks as they are the longest and most notable once-played sounds on moving objects) seem to start in the right place (in 3D space), but stay there instead of moving with the object (vehicles' sounds work OK though, as the engine sound seems to be dynamically scaled by the amount of force given by the player's input so it's not one file being played once and thus doesn't apply here). This leads to a zombie shrieking from your left hand side, you turning to face them or them moving to your other side, and the sound still remaining left instead of moving where the zombie is actually at. This in turn leads to believing there to be multiple zombies when there actually is just the one.
The sound effects also have no or close to no cooldown at all, leading to a zombie shrieking multiple times at the same time with their previous shrieks, sounding like multiple zombies at once when again, there actually is just one. Once the shriek sound is played, they seem to be able to do it again almost instantly (luckily not every frame, that would cause ear hemorrhaging).
In addition, sounds do not stop playing instantly when a zombie dies but play until the end of the file, leading to an uncertain moment right after a zombie is killed if it's actually dead yet or e.g. will start crawling, or if there are more zombies growling nearby.