When doing the Ancient Hunt Oozing Menace (may affect other hunts), the skill Luck of the Sea does not upgrade Rare Gilded items to Unique Gilded items. Instead, it simply renames the Rare Gilded item into an identical Unique Gilded copy of the Rare Gilded; no name change, no stats change, no additional skills, just the exact same Rare Gilded item with an orange border and Unique title.

Pics included showing:
Unique Mercenary Armor (should be Renegade Armor)
Unique Battlestaff (should be Battlestaff of Terror)