Oh god snap is a trash fire. They have a thing that inhibits updates for up to 14 days if an app is running.. but the Snap Store is a snap... and it runs in the background... so now everyone's had a notification that they should quit the snap store in the next 14 days but nobody knows how because it doesn't look open.
So the solution is to open the terminal because it always, always is.
https://askubuntu.com/a/1412580