Has anyone had this happen on facebook?

[JACQUE]

On the right side bar that shows your friends and if they are active or not, it has someone who is not my friend on facebook but is someone who I recently had been messaging. Funny thing is, this only happend to this specific person and nobody else that I message and hes number 2 on the list always. His position never changes no matter how many times I refresh. Its not even someone I message regularly. It was a random convo. The people i do message regularly dont show up on the side bar. So how and why is he on there if we arent even friends on facebook!? Anybody know or have had this issue?