Additional Drops
Items gained in the form of additional drops are not affected by drop quantity bonuses, additional drop quantity bonuses, drop rarity, or drop quantity bonuses for certain types of items, but are affected by type conversion and double drops effects.
Only monsters that have a chance to drop items can trigger this type of drop. Monsters that do not drop items under any circumstances (such as monsters summoned by a Plane Anchor) will not trigger this type of drop.