Adding or Removing Add ons on existing worlds bugs audio.

I've noticed that adding and/or removing add-ons and even texture packs in an existing world (with addons already present) has a really high if not 100% chance to glitch out audio. At first it’s a mild problem: Running and ladders audio is gone completely. And if done yet again or maybe more, the audio breaks even further: moving around makes running sounds non-stop.