Why did I not receive the Gear Up! and Stay Frosty Emotes in Fortnite Showdown after completing all the challenges?

After completing the final challenge in the Fortnite Showdown, you will receive the Gear Up! Emote if you joined Team Foundation, or the Stay Frosty Emote if you joined Team Ice King.

For more details, check out the event page: Fortnite Showdown (Opens in a new tab).