Was he using last year's route perhaps? Lots of people did stuff like that in TABR. People were riding the tourist board's route and not the files from the TABR site even though it explicitly says "THIS IS THE ROUTE TO USE" kinda shit. Idiots.
See my update. The Via Appia is well before Rome so that wasn't in the route last year. He follows the route nicely from Naples to Rome except for that section.
Previous editions started in Rome, so I think the hiking section is new.
http://www.italydivide.it/route
Update:
This is where he went off course, following the road instead of the steep looking hillside