When you damage a weapon or shield using two markers in one attack, is it one roll or separate rolls, and how is damage applied?

Question

Accepted Answer

It is a single attack, but the damage reduction applies to each die separately, so a d8 with 2 damage makes two rolls of d8-2. A die cannot drop below zero, and the damage is not applied to the total.

Xia: Legends of a Drift System

When you damage a weapon or shield using two markers in one attack, is it one roll or separate rolls, and how is damage applied?