This has been an issue since Festival of the Lost. If you have the Hunter’s Journal in your quests, the loot would be messed up. I tested this during FOTL, Dawning, and attunement (like with Zavala), and every time I remove that from my quests I get the right loot. For instance: few days ago I made a post about Onslaught does not drop the right attuned weapon, that time I had the Journal in my quests, today I deleted that and what do you know, 3 games in a row, got the right weapon.