Extended piston hitboxes do not include their arms

The Bug:

When a piston is extended, its arm isn't included within its hitbox. Please note that this report is talking about extended piston hitboxes and not piston head hitboxes.

Steps to Reproduce:

1. Place down a piston and activate it.
2. Look at the hitbox of the extended piston.
3. Take note as to whether or not extended piston hitboxes include their arms.

Observed Behavior:

There is no hitbox of the arms of extended pistons.

Expected Behavior:

A hitbox would be present on the arms of extended pistons.