Updating/Cooying world causes world to glitch out

Anytime I update a test world I've been using to check out the new snap shots...or say copy/recreate that world and play it in a new snap shot. The world glitches out really badly. Here are some screen shots of what I mean.
This has only started happening since snapshot 15w43c.

Not sure if this matters...but in most of these worlds i use the bonus chest option in the world creation menu.