This bug affects all items of all the sets that have been added to the game as the 5th set of each class. And it affects several other items that have been introduced recently.
I don’t remember with which patch the “new” sets came, though.
So, I hope they don’t need too much time to fix this.
But again, one has to question the release processes and quality of the QA team, if such a team still exists at all…
/Edit:
Game got another update (2.7.8.97927) of roughly 63 MB in size that seems to have fixed missing descriptions.