There is currently a bug in Diablo 4 that allows Echo of Lilith to continue to deal damage after being defeated in her second phase. In Season of the Construct, players will be fighting against mechanical scorpions, and Blizzard will be squashing some bugs of their own.
World Boss Caches Can Drop Uniques Gold Trading Much Easier on Console
Blizzard
Gameplay
Fixed an issue where the Echo of Lilith could still attack the player after being defeated during the second phase of the encounter.