A majority of the Dota 2 community is complaining about the unfair drop rates for the Immortal Treasure III. These complaints are mostly targeted towards the ultra-rare item of the treasure, Masque of Awbleb Bundle.
It seems players who have spent a lot of money in the game, leveling up their Battle Pass beyond the 600 mark have not been getting the Immortal bundle for Witch Doctor.
Now, this could be a bug in the update or worse, it could be a scam to further increase the prize pool as the only people who are affected by this are the ones who have spent a lot of money. Since there is a chance that those players will spend more, in hopes of getting their hands on the ultra-rare.