Gathering Blue - Matt?
On pages 162-163, while Thomas and Kira are looking for Matt, they go to his house and ask his mother where he is. After they finish talking and his mother slams the door, the book says:
"After a moment, Kira and Matt turned away."
It should say Kira and Thomas turned away, because Matt's not with them.
This is a very good book otherwise, and this is the only slipup I noticed.
Gathering Blue by Lois Lowry, I don't know if the version matters