persona combat, jacking out, or if the node your persona originates from is crashed.
from what i gather, dumpshock is a effect of the sudden cutoff from simsense.
having a "secondary" node (that is any node other then the node supplying the stats of the persona) crash or cut of connection do not do that, as the sim module of your "primary" node (comlink, nexus, whatever) is still in operation.
its a bit like that old statement about suddenly removing the VR goggles