First, Loyelle Tanlonikan (the start NPC) does not prompt the instance zone-in word. She simply says 'If you find out anything interesting, make sure to let me know' Very easy to not assume it's an instance mission and try the regular zone. While during the mission, the Defeat steps never partially update. You only get updates after both mobs are killed (and there was an up to 5 second delay on some of them). This is regardless of looting the collects on the mobs. [As a side note - the loot is underwhelming for 110]
Tempest Festival: They Came from Below Challenge - Reptile Displacement | EverQuest Forums (daybreakgames.com)