Ixchel's Torment Strongbox didn't drop a unique

As the thread title says the Ixchel's Torment strongbox did not drop a unique as it said it would.

Picture of what the box says it contains:

https://imgur.com/a/L85dNsD

Video of it opening:

https://www.youtube.com/watch?v=vsB9yFUrLHU