If you enable a banner topic, it can reappear when the topic is edited – and that is okay, however it will also reappear if you save your profile (that’s not okay).
Create a banner topic
Refresh the site
Refresh the site (verify it is dismissed)
Go to your profile, press Save (you don’t have to change anything)
Go to the homepage
Refresh the site (banner reappears)
Dismiss it again
Expected: Saving of profile doesn’t make the banner reappear.