The Scorn's +Damage is a single mod, Sinister Gorget's +Damage is two mods that got combined to one line.
The game has a bug with min damage (and even damage ranges on weapons), where it's calculating +Min Damage first. All +Min Damage is added to your weapon's base min damage and if this number pushes the min damage above it's base max damage, the max damage is moved to min damage plus one. Any +Max Damage left on the weapon or other items is then added to that adjusted value.
In this system (on almost all weapon types and combinations of damage increasing mods) just +Min Damage actually moves your min and max damage by the amount listed because it moves the adjusted maximum. The single +Damage Range mod (on armor and jewelry) doesn't benefit from this bug though, only plain +Min or + Min and +Max rolled as two separate mods but consolidated into one line on the item's tooltip are applied in this way (along with any +Damage Range or +Min Damage mods on weapons).