I agree that it looks totally normal here- I don't know if there were different camera angles on the CNN broadcast?
Here are some other folks dissecting the body language, but honestly, it could just be projection because they/I don't like the Romneys lol:
http://theimmoralminority.blogspot.ca/2012/10/apparently-not-all-of-romney-family.html
"Miss Ann took the child from PBO and gave him to willard and despite anon 10:55 - he was definitely reaching for PBO.
The other thing about that video, while PBO was interacting with the Romney family - Willard Romney was interacting with the Romney family and COMPLETELY ignored Michelle Obama. Romney doesn't have a sentiment of mixing with anyone other than his family and rich white folks. He would be President in exactly the same manner - get the help to talk to the lesser folk. He is revolting in every possible way and would insult every world leader if he got anywhere near the White House"
....
"It was a tender moment turned odd, after a rather contentious debate. Miles seemed to have a genuine desire to get close to the President who, in his usual fashion, was more than happy to engage with the youngster.
However this seemed to cause an uncomfortable ripple to go through the Romney family, which only dissipated once Mittens had pulled the young man away.
Not exactly sure what the dynamic is here, but once again the Romney family has given us cause to be a little disturbed by their behavior. "
...
"I saw that! Rewound and rewound and it looked like the boy was pushing away from Rmoney & reaching for Obama before someone grabbed him away! I was hoping to see clips of that floating around today.
"