When pillaring up in a straight column, at some point Minecraft starts to render transparent blocks. (attachment: pillar 1) If you log out and log back in, the blocks will be visible - but starting a new pillar or continuing to built on the previous one will render blocks again invisible at some point.

It seems to happen at the 2nd block in each upward chunk. (attachments pillar 2, a / pillar 2, b) - look at coords. Built another pillar, and the same thing happened at coords "CHUNK a, b, c" when B=1. (attachment: pillar 3)

After blocks start rendering transparent, any block placed next to the invisible ones sideways will also generate. (attachment: pillar 1, building to side) However, if you build sideways from a non-transparent block, the placed blocks will not render transparent at some point (attachment: sideways, opaque).