It has nothing to do with the third person, it's about the structure of the phrase and how the subject and object are connected through the verb, in Greek active or passive voice.
Remember that it is αναφέρω + object but αναφέρομαι + σε + object. From here, the example given "Don't forget to mention the party when you talk to Olivia. - Μην ξεχάσεις να αναφέρεις το πάρτυ όταν μιλήσεις με την Ολίβια." becomes "Don't forget to refer to the party when you talk to Olivia. - Μην ξεχάσεις να αναφερθείς στο πάρτυ όταν μιλήσεις με την Ολίβια."
Yes, a controversial issue in Greek. This word is a compound ανά+φέρω. So the augmentation ε must go before the second part, ανέφερα, according the rules of Ancient Greek. It is called internal augmentation εσωτερική αύξηση. But it is also usual to consider the word as a whole, since this word has been transferred by the scolars from the Ancient Greek to Modern Greek, in the form of katharevousa. It wasn't a word of everyday life that used by the common, simple people in Modern Greek. Having it in mind the word should take the augmentation before α but it never happens in Modern Greek, all words starting from a vowel do not take augmentation. So the form ανάφερα is used too. Notice that many words like this have the same double form. Also the augmentation is something that many verbs don't like much so both forms, with or without augmentation are correct. Example: ντύθηκα and εντύθηκα, with the first one more usual, but always έτρεχα, έφερα, because the stress is on έ. PS. Personally I don't agree to put an internal augmentation to all compound verbs, that do not come from Ancient Greek, actually Modern Greek does not "like" augmentation except when the stress goes on it :) Some more info here: http://users.sch.gr/ipap/Ellinikos%20Politismos/Yliko/Theoria%20Nea/auxisi-rim-NE.htm