Epic Cards Battle

The effect: 30% chance to double current DEF when being attacked, the chance is increased by 10% per other friendly "The Crusader" card on the battlefield.

DEF: 80

So I tried this out in a battle and the effect activated multiple times, but the DEF stat never changed. I searched on the forums but no mention of this card's effect. Can anyone else confirm that this may be broken?

It is likely that the defense increase is not permanent but applied as a chance roll of dice for each incoming attack. Once attacked his defense has a chance to go up for that one attack but not necessarily the next one. This is usually how they do it.