Piston retracting disapears if pushed out by another piston

Put the summary of the bug you're having here

What I expected to happen was...:
I thought the piston would detract then be pushed by the other piston

What actually happened was...:
The piston disapeared

Steps to Reproduce:
1. Put down a piston facing upwards
2. Then place another piston sideways on top of the piston facing upwards
3. Place a 2 blocks tall wall at the side of these with 1 block inbetween
4. Place torch on the top block facing the top piston and redstone dust right under the torch
5. remove the torch an the top piston disapears
6. The same thing happens with sticky pistons