Draugr DRFM Jammer Fails

Occasionally, when you're in the Draugr and getting the Missile locked on warning, activating the DRFM Jammer still allows the missile to be launched. This happens very often, at around a third of the time. It doesn't matter how fast you activate the jammer, the missile warning disappears but then the next message is "missile incoming" and the missile is on its way. It appears this happens most often with the Wildcat's AA missiles.