Lasers only roll 0 or 1 each for damage, except of course when empire attack bonuses are applied. If we say that ten of them roll seven in total, that's going to be seven 1s and three 0s. The defence gets to roll against each attack, but of course each attack reduces the maximum possible defence roll.

A far more thorough example of combat in DA is here. However, it doesn't factor in the new changes.

In case you haven't noticed, I was in that thread too
I don't think CodeCritter really meant *lasers* in that example, as if that was the case (and the example is really bad) some of the lasers from the second attack would have then be applied to another defense since the shields had already been depleted.
I think he meant an abstract 10 damage weapon, just for illustration purposes.

Laser cannons, well that makes more sense

Shouldn't this topic be categorised under Dark Avatar? It disappears quite quickly in the general Galciv II category.

What I would like to know it to what degree does this defence bug effect the current game?

Should I wait for a patch?

In my experience, it screws with any situation where the defense is off type and the weapon values are high. If you play a game where the tech stays fairly low, you probably won't notice it too much.