a derpie piston

Put the summary of the bug you're having here

What I expected to happen was that the piston activate, but it went wrong:

What actually happened was that i got a derpie piston:

Steps to Reproduce:
1. Put 2 piston on each other
2. make a wall with 1 block between
3. place a redstone torche on the side
4. and you have your one derpie piston