Crest of Desire cannot be chanced

As the title suggests, Crest of Desire cannot be chanced.

I created a Warlord + Crusader influenced base (ilvl 83) and bought the Trash to Treasure prophecy to chance the helmet, but it turned out that this doesn't work.

Doesn't seem like it's intended, because I couldn't find any information that it is a boss-drop or has any other drop restrictions.

This happened in Heist Softcore.

its restricted to unusual gem grand heists.

not a bug