I've noticed that Magai ships (frequent between mid-late Lt. Comm and early-mid Comm ranks, perhaps wider, but all magai ships I've encountered so far - ) When hit with jam sensors, they stop in their tracks completely. They stop all movement and just sit there.
This is somewhat understandable as they have no other target when you jam sensors, even with other ships in the area. However this is not a characteristic of jam sensors.
Other ships, when jam sensors is in effect, still flies around, seemingly keeping their strong shields on you so you canont focus on a weak side.
This effect is most obvious when you are in a mission where you face birds of prey, battleships, and magai. Magai stop dead, while others still fly around while under the effect of "jam sensors".