When collecting packed ice in icey-ocean, I created some ghost block.

I use diamond pickaxe enchanted efficience 5 and silk touch to collect ice, the pickaxe dig off ice too fast and creat those "holes". Maybe the game think I haven't damaged the block but in fact I have. 

These ghost block will get back to what it should be after the world reloaded. This also happen when damage crops: carrot potato wheat and beet. Sometimes when digging up stone too fast also lead to this result, but when standing with your head in the ghost block you will be stifle.