Doors can connect to fences when it would make sense to do so, so you can open and close the door to change whether or not the fence connects to it.

When you are inside where the fence would connect to the door, and you change the state of the door, the fence connects to it, while you are inside of it, making you able to walk right through the fence.

Also works perfectly with trapdoors instead of doors, as well as walls, glass panes, and iron bars instead of fences, though for walls it stops you at the pillar, being much less noticeable without another one behind it. Also it is much less noticeable if there are the respective block to the side of it, only clipping you partially into the block.

This is likely caused when Mojang made it so connectable blocks, like fences, walls, etc. could connect to any fully solid face of the block, instead of any solid block. This was probably done so that connectable blocks can connect to the back of stairs, but in doing so they made it connect to other blocks, like doors and trapdoors. Changing the state of a door is the only way to change the block connections without placing or breaking a block, so that is how this bug is caused

What I expected to happen was:

•  The fence would push me out when I change the state of the door

What actually happened was:

•  I clip into the fence when I change the state of the door, allowing me to walk right through it

Steps to reproduce:

1. Place down a fence, and a door next to it.
2. Go where the door meets up with the fence and go right up against the fence
3. Right click the door
4. Walk towards the fence

• Notice that you can walk freely inside the fence, until you leave the block.

Fix suggestions:

• Make it so that doors and trapdoors cannot connect to blocks like fences or walls
• Make it so that when you do the steps provided, it pushes you out of the solid part of the block

(Note this bug was marked as a duplicate for MC-122376 when it is not. I created a new ticket (MC-227095) because of this)