Mining Block 2 block high shows cracks in the side you're mining

I'm pretty sure this Works As Intended as things that are 2 blocks high like doors, tall grass, etc. are made out of 2 blocks (the bottom and the top part), not one single block.

If you look at the outline selection you can see that it only selects the side you are looking at.

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I don't think this is actually incomplete, as i understood what does the reporter mean. He probably means that when you mine something that is 2 blocks high, like doors for example, it only shows the cracks on one side of the door (the upper side or lower side), depending which side are you facing and breaking.

One of the steps to reproduce will be:

1. Place a door on the ground;

2. Switch to survival mode (if you are not in survival mode);

3. Start breaking the bottom part of the door;

4. The bottom part of the door will start to crack, but the top one will NOT start to crack, even if you mine the door until it breaks;

5. This also applies if you break the top part (the bottom part will remain unbroken instead)

I still think this works as intended though.

Here is some images of the "bug" shown: 

This is intentional per the fix of [MC-161083]