Have a look in export_descr_character_traits. Do a search for the first of the offending traits, (ctrl+f and type battlescarred). Keep going until you find the trigger section EG.
Code:
Trigger Battle_General_Took_Hits
WhenToTest PostBattle
Condition GeneralHPLostRatioinBattle > 0.3
Affects BattleScarred 1 Chance 30
Affects Brave 1 Chance 20
To reduce the chance of getting the affect BattleScarred, change the Chance to a lower percentage. Once you have selected a number your happy with, continue to search the rest of the file, quite a few traits have multiple triggers. The next one in my file is,
Code:
Trigger Worthy_Of_Adoption_3_VnV_Trigger
WhenToTest OfferedForAdoption
Affects BattleScarred 1 Chance 17
Affects Intelligent 1 Chance 8
Affects NaturalMilitarySkill 1 Chance 8
Affects GoodCommander 1 Chance 80
Affects Handsome 1 Chance 10
Hope that helps...