This is a bug that I noticed a while ago, and forgot about. When looking at the SWDJ blocks at certain angles, it won't render. In the Beta for U43 and lower (42 and lower for non-beta's) it would work properly. Here are some images: 

That happens to me too.

Pretty sure it happens to Everyone.

Bluey26 was the first person I know who noticed. It is really annoying, which is why I brought it up (before U44)

Yeah. I've just always put up with it because it's happened to my tardis a few times xD

It also happens to my beacon I use for a console beam sometimes and I think that's cool how it will vanish and come back it adds a cool effect to it. So the glitch has it's advantages and disadvantages like most things in life xD.

Fixed in update 44. It was a bounding box issue