Hay Bales and Pistons unbreakable with tools in Adventure mode

I'm making an adventure map and I lined up most of the placable blocks to find the tools you need to break each. I found that you can't break cactus (but it's breakable by removing the sand block beneath). Also I found that I could not break pistons and hay bales with any of the tools.

What I expected to happen was...:
Cactus breakable by sword, Hay Bales breakable by hand, and pistons breakable by pickaxe.

What actually happened was...:
I could not break pistons and hay bales with any tools. I broke cactus by destroying the sand beneath.

Steps to Reproduce:
1. Put cactus, pistons and a hay bale.
2. Try to break them in gamemode 2.
3. Notice that they don't break. How am I supposed to get them now?