Why is deleted account/friend still showing up on my chat list?

A couple of months ago, a facebook friend deleted her account due to the current issues surrounding fb. And, as you would expect, her name/photo are completely gone from my friends page. But here's the thing: her name/profile photo are still on my chat list appearing on the right side of my fb page. And every so often, her green light/dot appears which, as we know, indicates that someone is logged on to fb using that account. How can that be?

She says that she doesn't have a fb account any longer. But even if she lied to me and just un-friended me why would her name, photo and, most importantly, her green light still appear on the chat list? As I said, she is totally gone from my friends page.

She thinks it might be a phony page using her name which was created many months before she cancelled her real account. But, as happens with these hacked/phony pages, I received a friend request and immediately deleted it. Since I am not a 'friend' on this phony/hacked page I do not receive any posts from it (if there are any), receive no notifications from it, nor does it appear on my friends page. It is, like any of the other billion people who I am not friends with, non-existent to my fb page. It seems pretty clear to me that the phony page didn't somehow 'step into the shoes' of the real account when the real account was cancelled.

Can someone please provide an explanation how this can happen because I'm at a loss for one? I don't think my friend would lie to me and say that she cancelled her account when she didn't, instead just un-friending me. But even if she did that, her name/photo/green light should not appear on my chat list. I'm at a loss for any explanation. Help.