What I expected to happen was...:
2 sticky pistons to stay retracted.

What actually happened was...:
The bottom sticky piston extended.

Steps to Reproduce:
1. place a sticky piston sticky side towards your player
2. place another sticky piston ontop of the other piston, again sticky side towards your player
3. place a redstone block on the top pistons sticky side
4. place a redstone block on the bottom pistons sticky side
5. the bottom piston should extend but if this is done the other way round, bottom piston then top piston, then neither will extend.