UPDATE: Epic has autocompleted the challenge for all players
One of the Fortnite Season 7 Week 5 Challenges is causing some players to have trouble completing the "Deploy Alien Nanites" quest.
These kinds of issues are rare but do pop up from time to time, and Epic is currently looking into why this is happening with hopes of resolving it soon.
Unable to Complete "Deploy Alien Nanites"
The fourth Legendary quest of the Fortnite Chapter 2, Season 7, Week 5 challenges requires players to toss Alien Nanites and create an Alien Biome.
Unfortunately, some players are having issues with Fortnite tracking that they have thrown the Nanites as the challenge requires.
It does not seem to be happening for everyone, and there are reports of players having success completing the challenge by throwing the Alien Nanites without using aim-down sights (ADS.)
Hopefully, Epic Games will have an update, and a fix, soon.
Until then, it is recommended to keep trying to toss Alien Nanites in different matches without using ADS until the game successfully tracks the quest completion.
It would be great if Epic fixed the issues with Abductors simultaneously as they fix these issues with the "Deploy Alien Nanites" quest.