Game will lag when certain sounds stops playing.

There are many ways to reproduce this, like place a couple of pistons and setup a clock so that the pistons will fire in certain constant times. Run the clock, and connect it to the pistons, then slowly walk/fly away from it. Then most likely the lag will happen. I do have the right system requirements to run minecraft so this is obviously a bug. I've attached a world download and there's instructions what you guys should do to reproduce it.