It might not even be the rolls, but other hidden mechanics that aren't displayed.
We could know for certain if Larian would just add the option to view combat rolls and see if I really was rolling 10 or less 20 times in a row on a 50% chance.
You can see the rolls if you expand the combat log and hover over the hit/damage/miss text. It shows what number you rolled on the d20, all the bonuses, and the target AC/DC.
Or do you mean something else?
