So, 8 Imperial Infantrymen lose against 7 looters head on, and after grinding through my infantrymen, they still have 4 guys alive. I have a suspicion there is something about:
1. Troops hug eachother in battle;
2. When they hug, long weapons, such as spathas and bastard swords are ineffective;
3. Regular infantry weapons are really slow, namely the two mentioned above, which explains why looters win so easily;
4. Because the enemy has fast striking weapons, even if cheap, means shields make no difference in battle.
In comparison, the same 8 guys fared better when they were recruits, killing 11 looters in an earlier battle.
Also, I got this bug in Phycaon. All files validated.