This in a somewhat rare bug that I have managed to encounter a couple times with this mod loaded, but only in the Jungle each time. Other mods were loaded at the time these happened, so it could unrelated to High FPS Support. I'm posting this here as High FPS Support is mentioned in the log and I've only encountered the warning after adding it. Sad to say I don't know of any of the other causes of the warning. The warning appears as a dialog window, but does not crash the game.

The relevant part of client.log can be found in "Zombie Sound Warning" here[drive.google.com].