When Redstone is directed into a piston or sticky piston from the side, it still behaves like a straight line of Redstone, causing things to be powered that shouldn't be receiving power at all. 

Steps to recreate: I've provided a handy screenshot with measurement lines for the small 2x8 example that I've built to show off this bug.

In the example scenario, the Redstone lamp and the "pink" sticky piston should remain unpowered, yet they receive power from the lever anyway.