Redstone Error.

I tried to put two pistons on top of each other, but the one on the right would not properly extend instead it looked like 2 extended piston arms instead of the what its supposed to be.

Steps to reproduce:
Put two pistons facing downward and make it so that when you power them the top one extends the bottom one down, which then extends another block. when the power is removed the bottom one temporarily loses power, the top one brings it back up and bottom one extends again retrieving the black.