not sure if this ia a bug or not
Yes, some time ago I realized that. I just realized someone had added me as friend when I occasionally checked the Followers tab. Not notifications, not questions or anything was given. They could have me in their list and I don’t having them in mine for ages if I didn’t check that tab. I’m not sure if it’s a bug or not and I thought it was a normal behavior at first glance (although odd).
As a suggestion for your bug report, you could edit title and put a better text in there. Try to use something more descriptive like “No notices when someone adds you”. That way there may be more changes to get it looked by a dev. You can do that by clicking the link just below the title.