Well, I can destroy them, but it has to be with the right tool. Pick to destroy stone, shovel for dirt, and so on. But in the past I could pound on about anything with the "wrong tool" and destroy it eventually. Now I have to keep switching between tools ALL THE TIME to destroy the kind of block. Any ideas why? I noticed it when I made 2 pistons, then tried to destroy them and couldn't do it at all. Had to switch to creative mode to get them out of the way.