FB contact add to contacts

[tony8a]

I got a txt from a friend on Fb who's number I did not have stored. It put the name in because it found them on my friends list, though they are not currently a contact in my phone. When I would go to try and add them it would act as if they were a contact already and as soon as I deleted our conversation I no longer had their number in my phone. I think it was because they have their number on FB and I was able to get it from the FB phone book, but this is rahter annoying since it happened several times as I was trying to populate my contact list.