I've had a look at the issue with the Cardinal. It is strange. He is just Peter Scherer if I load the savegame up in M2TW or Medifixed M2TW. He was also Peter Scherer that when I started a new campaign in M2TW. However, when I started a new campaign in Medifixed M2TW, he was "Peter the Righteous" and had an extra virtue (an extra +3 peity being incidentally not reflected in his piety).

I conjecture that characters may randomly spawn extra traits when you start up a campaign. The warmonger title was probably something he got when I started a new game last night (note: I did absolutely nothing in game, so it must have been spawned on start up), but did not save.

It also seems that Medifix may not be a perfect fix (the extra virtue not being reflected in his total piety).

However, I think we just press on with Medifix and our kinder, gentler Peter.