Blue Screen /Black Screen when making changes to blocks..

Does anyone have any idea why the client blue screens then black screens when making changes to blocks in code, and only sometimes?

I've Google'ed around and yet to fine one concise answer..

Basically I'm looping in a cuboid area changing ANY solid block to air, being careful not to modify the block space occupied by the player at the time of the change..

Sometimes it will blue screen and other times it works..

The only solution is to teleport the player out of the area then return them when the changes are made. This makes me think it is an issue when a change occurs where the player is however I am avoiding the players location from feet to head, and it still happens. (Very similar to the world edit bug).

Anyway just looking for guesses opinions or facts here.