@Skirmisher Because I blocked her (but not instance blocked at the time), the notification didn't show, however the fact that she mentioned me meant that her toot was still sent here, as mentions override everything short of an instance block when determining which instances to send to
@Skirmisher And because she mentioned me, Mastodon lets me view the toot despite the fact that we no longer followed each other.
There's no trickery here at all, I haven't modified my instance to do anything untoward, I didn't have to view it in the admin panel or anything sneaky like that... that's just how Mastodon works.