Charisma or other stats have very little influence on dice rolls, if any at all. Maybe it's just bugged, and the logs doesn't show anything about these rolls (just fight related), so remains a mystery.
As a non D&Der this irritated me but it was explained it becomes a more significant thing at higher levels (at least in theory). But I still find it irritating; at least on my second play-through I knew to not waste any points on charisma because rolling a 3 is as much of a fail with high charisma is it is with having all the wit of... well, <insert witless sociopath here> kinda thing. And I roll a lot of threes, because it's apparently my unlucky number or something.
