hero4hire
Explorer
(Hex actually cannot make that roll, as natural 20's don't autosucceed skill checks )
Hmmm...Is that written somewhere? Interpretation?
This is what I could find. Emphasis mine.
If you roll a 20 on the die when making a check you’ve scored a critical success. Determine the degree of success normally and then increase it by one degree. This can turn a low-level success into something more significant, but more importantly, it can turn a failure into a full-fledged success!
So on a roll of Natural 20 it would seem to me you determine successes (in this case none) and then add one success.