It's the mid-1400s in my current game as the Spanish and in the hopes of unlocking the Turkish faction, I convinced the Pope to call a crusade to their last province, Trebizond. After my crusading army arrived in the province and killed the faction heir I noticed something wierd about the king:

At first I was astonished that he had near maxed-out authority (I've rarely had a king with more than like 5). When I assualted the settlement I thought I would look at the king's stats to see what made him just such a great king. Rather than having traits that would boost his authority he had quite the opposite. He was loaded with traits with negative authority (i.e. insanity and a handful of others). I went ahead and counted up all the authority points to find that he had -9 in total (including positive points) yet it showed up as +9 in the game.

This seems suspicious at best and while I haven't had any such problem when I'm playing, it still makes me scratch my head when I see it happen to a computer.