Ask HN: I got email asking to approve member to Facebook group,but I'm Not admin

I just got an email of the form: (name) asked to join (Facebook Public Group name) ... which is a genuine email from Facebook and not a phish (the clickable links are all genuine facebook.com URLs). I am a mere member of this group and am not, and never have been, an admin. (Not that there's anything wrong with that.) The link underlying the "Respond to Request" button brought me to the genuine "Member requests" page with this one request as its lone item. I've never seen this failure before. It's not a meaningful "breach" in itself, but if it indicates a broader defect in Facebook's auth process, yikes.