The World Does Not Render Correctly

I have noticed this a lot when playing the recent snapshots for the 1.8 updates. The world does not render blocks correctly and they sometimes are invisible until another block is placed or broken beside or near it, I have noticed this a lot in videos I have watched of the snapshots, so I am pretty sure that it does not only effect my computer! Sometimes the blocks are broken but are still there for a few seconds, like ghost blocks.