Ah, thank you, it works! I had not had him go away from the party members, and I was also trying mostly in Athkatla, since I finished everywhere else before I went to the Underdark!
Once I headed to the Temple Ruins and had him walk a ways away, it triggered just fine! No more 9 dexterity!!!
I'm playing the latest version on kerzenburg from May of this year, v11 I believe?