The problem is that players do not read what they’ll be getting.
This is the Mourning Haul bundle…
This includes a Masterwork Gem Random Chest as part of it…
Pay attention to the description of the chest…
When used, select six 5-Star Bound Legendary Gems (Quality 2). One of the six gems will be randomly selected.
There are currently 21 different 5-Star gems in the game. This chest allows you to select 6 of those 21 gems and then randomly gives you one of the 6 you had selected.
When you read one of the six gems why did you expect all of the six gems?
The description on the chest is clear.
This is not a bug.