Flux-switching phenomena characteristic to multipath cores result from the dependence of switching in one leg (a physical branch between the core junctions) on switching in the others. Reversible Δφ in a leg driven far into saturation may cause appreciable irreversible Δφ in other legs. This effect is analyzed by tracing the variations of φ and F of each leg of a three-leg core under two conditions: a positive drive on an inside leg, and a negative drive on an outside leg. Due to variations in air-flux linkage, a tight winding on the driven leg minimizes this effect. Upon termination of the drive pulse, the legs are shown to be left in a ``stressed'' state; i.e., a residual H field, sustained by magnetic poles near the leg junctions, remains in each leg.