Targum Bilangan 26:11: Targum Jonathan & Targum Jerusalem

But the sons of Korach were not in the counsel of their father, but followed the doctrine of Mosheh the prophet; and therefore they died not by the plague, nor were smitten by the fire, nor engulphed in the yawning of the earth.

But the sons of Korach, who were not in the counsel of their father did not die.