Buried Treasure Map loot spawning as named Empty Map

Looted two ocean ruin chests and one item in each was an empty map named "Buried Treasure Map". 

What I expected to happen was...:
Buried Treasure Map would be the item with an X at the location of the nearest buried treasure.

What actually happened was...:
Item is just a named empty treasure map. When I found the second one I used it to confirm if it was just a visual bug but it indeed mapped the local area and name was replaced with "map".

Steps to Reproduce:
1. Find ocean ruin with a chest.
2. Open chest, find empty map named "Buried Treasure Map" as a loot item.