ci_activity behaving oddly in Notifications

[herebebeasties]

I have the GitHub app installed on my org, with access to all repos. I'm getting ci_activity items in the notifications panel, which look like this:

In addition, if I click on the ci_activity label to filter to only those, the "Subscription reason" pane in filters then looks like this:

Note the 1/12 with nothing selected. It seems that CI Activity is a hidden item in here?
(If I check all the remaining items, I get 13/12 in the status bar for that.)