Seems to have been something people have been discovering now that it's been released on digital. CBR also had an article on this as well but I can't seem to locate it at the monet.
https://www.youtube.com/watch?v=s5GSPClmZoQ
I think it shows up a few more times during the middle act of AOTC, sort of a kind of 'mystery' music.
Similar music also plays when Palpatine is taking the life force out of the Dyad to restore himself.