Pufferfish can sting entities through blocks

Pufferfish can sting you through blocks and corners, which doesn't make sense as it is a physical attack.

How to reproduce

1. Make a box with 2-block tall air inside, without corners.
2. Summon a pufferfish with water inside.
3. Get close to the corner of the box.
4. Notice how you get hit by the pufferfish.

Expected result
The pufferfish wouldn't be able to sting you through blocks.

Observed result
The pufferfish hits you through the corner, even though it's a physical/melee attack.