Ender Dragons can get frozen by blocking navigation nodes by placing blocks on their positions

Ender Dragons will freeze and do nothing if they fail to find any path. And you can simply destroy all the crystals and place some blocks to do that.

Steps to Reproduce:

[Step 1]

Go to the end. Destroy all the end crystals.

[Step 2]

Place all the blocks at a height of more than 200 at these nodes:

40:X 0:Z
28:X 28:Z
0:X 40:Z
-29:X 28:Z
-40:X 0:Z
-29:X -29:Z
0:X -40:Z
28:X -29:Z
20:X 0:Z
0:X 20:Z
-20:X 0:Z
0:X -20:Z

  [Step 3]
Wait for a while.
Or restart the server/save and enter the world again.

Observed Results:

Ender Dragon stays still and freezes. She will do nothing and she won't even attack players when she got hurt.

Expected Results:

Ender Dragon won't be affected by the blocks the player places. She'll keep doing what she should do, like chasing and attacking players.

Screenshots/Videos:

Check the attachment file for reference.

Also check Rays Works, and Igna778's videos for more info:

Ray's video

Igna778's video

Notes:

This can be done in survival mode. And this bug has existed since the dragon's AI was updated.

The dragon in the overworld can also get frozen without using commands. All you need to do is to place all the nodes and remove one, then wait for a while.