When you're breaking a block and the block directly in front of you goes out of range for either of the two reasons:

• You break a block, next block is out of reach
• You look away, look back at a block
  The block you next try to break will not begin to break, you must unclick and reclick to activate the tool.

An example of this can be seen in the video. In this video I had to use my mouse click four times as opposed to just holding it down and breaking all the blocks I broke in one action. This is in contradiction to the Java edition and older versions of the game. This is also down right frustrating.