Hi NotApxllx-_-, thanks for contacting us about this challenge.
With any rewards we will always ask players to wait 24 hours for the items to appear in your game.
For certain event rewards or Twitch streams, usually these rewards will appear in your account, one day after the even has come to a close.
Recently we discovered that with some of our Ubisoft Connect time-related / weekly challenges, progress was not being counted so we rolled out a fix for this on the 30th October and this should fix itself and should have correct progress by the end of this week for most players.
To see more on our post on this, please check out this thread on missing content that pertains to Siege as well -