Bug in duel mode. I have the hilt and blade of Quel’Delar, but it is not assembled into a weapon, but is present in the form of two cards in the deck.
Class: Warrior. Perhaps because of the treasure: Grommash’s Bracers, as the blade immediately appears in the hand as a separate item for (0) mana.
There are screenshots, but they are not skipped by the forum …
UPD: I got another blade, I decided to take it and it worked. Total: I have two blades and one hilt in the deck.