When enemies Liberating Exhortation is used on an enemy you have effected with Deep Wounds, all enemies (even different groups you attack) from then on are permanently immune to it (it says Deep Wounds is suppressed) until you reload.   While the bug isn't so bad as it is fixable with a reload, it does mean Deep Wounds is more or less worthless when fighting any group with a Paladin as you can't fix it mid fight.