Processing order creates BUD

So I had made the system shown in the screenshot #1.
As you must realize, when I turn off the circuit, the piston further down on the picture will retract in the same game tick as the one on the top. But it actually retracts second, according to the processing order. But the piston on the top of the picture does not extend! Realize that if I use the system in screenshot #2, this does not happen. This brings me to the conclusion that it has something to do with block 36, because it only appears when pistons are retracting a block (not sure about that). Also this (I think) is the same bug that causes the double piston extender going upwards with the torch.
And this has happened in all version that I know of (not only 1.8.7).