Issues when breaking blocks in creative mode

As you can see, i'm trying to break a block by tapping the break button, which is expected to break the block instantly. But in this case, i need to hold the button for ~0.5 seconds to actually break the block.

 

There's also another issue, when a block is in the fast bridging position (1 block below and 1 block in front of the player's feet and no blocks below that block) it cannot be broken, it just flickers between air and block.