This happens when you update blocks' state.

Steps to reproduce:

Remember to set your game mode to survival.

1) Get yourself a shovel with the enchantment of Efficiency, at least level IV.

2) Mining dirt blocks quickly and observe when those blocks actually disappear.

3) Get yourself a stack of dirt blocks.

4) Place them in a line quickly and observe when those blocks actually appear.

Expected:

They should appear or disappear visually at the point when you placing or mining.

Observed:

Sometimes they remain invisible or stay still for a second after you placing or mining.