This issue happens when you hit a block with a new pickaxe to break it in survival mode, the block is not broken. If the game mode is changed from creative to survival, the bug does not occur. If you keep hitting it after not breaking, the animation of the block breaking will not appear but it will break. It happens with any blocks that are hit with a new pickaxe, also with any pickaxe. Again, only in survival mode with cheats not activated.