Instinct
Something is wrong. Arren Kae knows this in the way she knows there is a stranger in the house, the way she knows the baby has died. It is not a quiver in the force, a crude echo of cause and effect and soon-to-cause-and-effect. The force screams constantly now, and any finesse in reading its signals can take hours, days, weeks. And the force can lie, just as any living creature lies, in order to push things in the direction it intends.
No, this feeling is instinct. Honed from before humanity used the force and never truly lost, despite becoming dependant on machines and artificial means. Something is wrong, and locked away in her own self-imposed exile, dead to the galaxy, the feeling lingers for months. It takes months, for Arren to learn her student has returned, and that Revan's opening gambit was to slay her lover.
Nearly a decade later, Kreia stands and leaves the Ebon Hawk. There is no tremor in the force, no echo down her bond. But she knows something is wrong.