Well, a 2018 announcement is insane, that probably is a random glitch. I recommended not saying anything on here for at least 4 months and if you still have issues then contact Fandom staff.
If you've made any sort of edit or post on a wiki in the last three months, then you'll get notifications from it until you become inactive for three months. That being said, a notification from 2018 should not be possible, unless it was re-highlighted.
There are methods to surpress notifications from individual wikis, but they involve a bit of programming, so it's generally only viable for technically inclined users.
