When I mine to fast "ghost blocks" generates.

I want to make a nether-hub so therefore I mine a lot of netherrack. When I mine I use my diamond pickaxe, enchanted with efficiency V. Because of the efficiency the netherrack gets brocken really fast. When I run to pick ut the dropped items I get stopped by invisible blocks. I believe that the game doesn't react fast enough for the block to disappear, but instead just becomes invisible.