Magnavode

I tested in 16w02a and the current 16w03a, both in all cardinal directions. I did not run into the bug.

The piston in the image you just posted is facing east, however the faulty piston is facing west (it is placed while facing east).
I double checked using the sandstone textures, however I really tired right now, maybe I overlooked something or I'm missing the point of your picture.
Not that it really matters, it should be easy enough to find if you place 4 pistons around a redstone torch.

Only 1.8.1-pre1 has the adjusted hitbox (not 1.8). 1.8.1-pre2 is back to the old malformed hitbox.

Edit: version fix 1.8-pre1 => 1.8.1-pre1

Can confirm what George Gates commented.

The piston arm's hitbox has been adjusted, but is still malformed.