The script should be stopping soon as Vish dies. But tainted eggs and mournful spirits keep spawning. If you don't keep killing the eggs they will hatch the corrupted drakelings. Makes for a bit of an annoying part of managing loot and then folks going AFK after kill. The event should stop spawning eggs and spirits soon as Vish is killed.
Verified. Active ZCDs that are not up when the raid completes will remain active and continue spawning once the raid has been completed. Created an internal ticket. Thank you for letting us know!