Player appearing to freeze / laid blocks returning to inventory

Sometimes after laying a line of blocks the blocks suddenly disappear and return to the inventory within a few seconds.

After harvesting a line of wheat the wheat will suddenly reappear in the ground after a few seconds.

 

When it happens in 2 player mode - if p1 is building he will appear to freeze from p2's perspective for a few seconds then p1's laid blocks will disappear and return to the inventory.