That’s not true.Actually 7 were leaked in some form.
Love Never Felt So Good Leaked in 2011
Chicago Rock Version Leaked in 2010/2011
A Place With No Name Leaked in 2013
Slave To The Rhythm Remix Leaked in 2010/2011
Blue Gangsta Leaked In 2010
Xscape Leaked in 2002
Chicago (2010 version/Rock mix) was leaked AFTER Xscape was released.
Nobody had heard “She Was Lovin’ Me” before Xscape’s release.
It was one of the two songs not heard before. “Loving You” being the other one.
And reg. the 24 tracks again:
That was the amount of songs they chose the final track list from. (At least that was the official stance on the matter, that they proclaimed within promotional material.)
So if we take that 24 at face value, there are now 16 songs left, after the release of Xscape.
16 songs in that specific state, they were looking for, for the Xscape project.
That doesn’t mean there are other songs in different states. And it doesn’t mean they have found other ones since.