Mono-stable circuit, one tick pulse, powering a block next to a piston will not always cause the piston to extend and retract as it should. With some testing, the results of the circuits (all facing the same direction) depended on Z or Y coordinates. Circuits at a negative Z coordinate, for example, would never fire, but an identical circuit a few blocks away at a positive Z coordinate would fire every time without fail.

Example circuit shown below with F3 toggled on.