Summary - When Insta-mining blocks (Efficiency 5 + haste 2) or (Efficiency 9) "Shadow Blocks" appear for a brief moment before they vanish. This also seems to cause some minor (Almost unnoticeable unless your PC is lacking) lag issues on the client-side. These shadow blocks only seem to show up when the blocks are NOT naturally spawned. Only when a mine resets or //set is used on an area. 

I have had this issue for some time now, and not a single person I have contacted has been able to think of a fix. All I know is that it's an issue with Minecrafts Light Engine.

There was a post similar to this a while back on bugs.mojang.com, but it has now been over two years and this has still gone unfixed. 

I'm wondering if anyone knows any possible solution to this. It's extremely infuriating and I have tried everything I can think of, to the best of my abilities that is. I have included a video that was people can see exactly what I'm talking about.