Redstoneblock powers Piston beside Piston w/ Redstoneblock

What I expected to happen was...:
Nothing

What actually happened was...:
A piston beside a piston with a redstoneblock above extended after putting a redstoneblock on the it.

Steps to Reproduce:
Check the vid out: http://www.youtube.com/watch?v=07EtoKZSEO4

It looks like this is a slightly different bug as this one was reported previously, but it's different.