I just found a The_Goldleaf_Blade in a late campaign mission. It triggered the tutorial text popup where gary explains on how to equip an item.
I today received The Goldleaf Blade as the club reward for finishing "Temple of Scales". This triggered two Gary dialog pop-ups which appeared in the bottom of the screen unlike his usual DM-ing ones. The first told me to move the sword to the empty hand of the figure at left. Gary waited for me to do so even though my character had no gold power balls and could not hold onto the sword. Dragging the sword over anyway satisfied the script and let play continue. The second dialog said "By equipping The Goldleaf Blade, Borgo put some great new cards in his deck!"
That's a shame. It's actually a very nice weapon. Is the bug really so nasty that it can't be fixed and instead the weapon must never drop again?