Parry in Offensive Stance?

Please, I just had in a game a skull warrior parring an attack in offensive stance now, since the information the tutorial and the offensive stance description are quite explicative in saying that there should not be parry chance at 0 parry rating... I am asking if exists a minimum parry cap or it' is just not working as intended.

Or if someone please could explain me what could have happened.

That's happen to me two or three time... probably seem that a 0 Def doesn't mean an automatic success for the attacker but just that in the formula DEF = 0.

For example if a unit with ATT=0 attack a unit with offensive stance it still have 20% chance to parry. So could happen that a unit with offensive stance parry also if the enemy is encircled or if the unit attack roll=100 that's an automatic fail if i'm correct.

And you must remember about modifiers
for example -15% for each other enemy in fray ... its easy to make 70% or less even from 100%

And you must remember about modifiers
for example -15% for each other enemy in fray ... its easy to make 70% or less even from 100%

and that both the offensive and defensive stance, remain active the turn in which the cast and the next round until active unity