There are a few possible reasons for this:
-You and the person may have recently added each other on Snapchat and they appear in your “Recents” list because you are both new contacts.
-The person could have recently Snapchatted you and they appear in your “Recents” list because they are one of your most recent contacts.
-You could have recently viewed the person’s Snapchat Story and they appear in your “Recents” list because you are one of their most recent viewers.