From D&D Wiki
There is a double comma under the Shadow's Armor Class, right after the parentheses. Someone should fix this.
Armor Class: 13 (+2 Dex, +1 deflection),, touch 13, flat-footed 11
I noticed the same thing in the Young Adult Red Dragon Skeleton section. I don't know if there are other sections with this mistake but it might be worth checking out.