There are now 4 offset graphical copies of the base pieces/gibs (the lowest one is the original).

I don't know what causes it, I'm ussually wandering around mining.

We've known about that glitch since B18.
We have no idea why it happens.

Lag causes the game to draw certain areas badly. As it happened with B18, it likely has to do with changes made to the engine at that point in time.

It's not so much a mystery as it's not a major concern. It's basically impossible to do without using mods and objects at the very top of the screen, so it's not a big worry.

Was worth checking in about.

Thanks.