OK watching the HD footage of the stage and screen, the mystery of the Richie mistake is pretty simple. It is NOT a broken string as someone postulated in another thread.
He plays the song on the upper neck with a capo and the solo on the lower neck with no capo. He forgot to switch back after the solo and after hitting the right fret on the wrong neck he quickly grabs the other neck to continue.
probably a mental slip
Dave
I may try to post it up to youtube if folks actually care.