redstone block inadvertently triggers sticky pistons its not connected to

when placing redstone blocks on 2 sticky pistons, one piston face up on the ground and the other piston 2 blocks up and one to the right, if you place the redstone on the face of the floating piston, then one on the face of the grounded piston, they both activate, while if you place one on the face of the grounded piston, then one on the face of the floating piston, they stay inactive