Naruto never sensed Minato
This is a simple theory on the sudden buzz on the forums. Basically, Naruto never actually sensed Minato. Why do I utter such things? Easy:
1. Naruto is not even at his basic SM. We know that's the lowest form in which he can sense things.
2. Naruto in base form, can't sense. He has no sensing capabilities that we've seen.
Another argument someone could say is, Kurama sensed him. No, that's not the case. Though we've seen Kurama throughout the series say things about certain peoples chakra, he's never actually sensed them coming, or going. Going to list some interactions I remember.
1. Sasuke in Naruto's subconscious. Sasuke was holding Kurama, which is likely why Kurama could feel Sasuke's chakra nature. He could sense the evil, as he himself is a mass of evil.
2. He also compared Sasuke's evil nature to Madara's, as he was once controlled by Madara, and they obviously shared chakra(at least Madara fed him chakra to keep him under control).
3. When Kurama was about to break loose in the Pain Arc, Minato intervened and helped his son. Kurama remember Minato's chakra, as Minato had used sever jutsu on Kurama. It's like getting a taste of a lollipop then smelling that flavor again.
There might be a few more instances, if so post below.
Basically, there's no valid manga proof that would prove Naruto sense Minato, or anyone else coming near him. I think when Minato showed up and asked that question, Naruto was simply answering generally(scan below):
Notice he says, "You were right on time, Dad!!" You can see the surprise in the text via the two !'s. Surely it's understood that this is speculation, but it holds more manga fact than simply saying; Naruto sensed him, with a baseless argument.