Wrong NPC "to hit" calculation ***Spoilers on one stats of one NPC***

I was looking at the to hit of Rigg Gargadilly (River Runs Red - Forgotten Keep) and it shows +6. However BAB (+4) + Weapon Finesse (+9) + weapon (+1) it should be +14.
Am I missing an information? I didn't see anywhere an info that his stats are impacted by something.
Do you fix it or leave it as printed?

It shows +6, it's supposed to be +16; the "1" was missed.
(I don't have the book handy so can't tell you how it was calculated, but I remember reading that from someone important enough to believe on here when I was running it. Possibly in the stickied thread for the book.)

+4 BAB
+1 size
+9 finesse
+1 magic weapon
+1 weapon focus