Not sure if thats a bug, but it feels like one. A Guardian can reach you on the rooftop next to him if you are standing close to the ledge or on the bilboard. Notice that on the second and third picture, if Abrams moves one step the Guardian can no longer reach him, even though it seems hes actually standing closer to it. It would be way more intuitive if Guardians couldnt reach the rooftop at all and the player cant damage it while standing there.
