Currently, dungeon loot tables cannot be applied to custom blocks with custom inventories attached.
For example, if I use the command below and apply it to a chest, I can open the chest to find dungeon loot. But if I run the same command on a custom block with an inventory, it will not have any loot inside. This would make custom structures that contains custom chests with loot possible.
Attached is my workspace, the revelant elements are named CrateGUI and AzureCrate.
/data merge block ~ ~-2 ~ {LootTable:"chests/simple_dungeon"}
Issue comments
I tested and it worked. But I had to specify absolute coordinates, or offset myself properly above the chest to apply. Same happened with vanilla chests.
Also:
]
}
],
"name": "natureplus:azure_crate
}
One of your loot tables has broken JSON and it has locked code so I guess it's a typo when you were editing it.
I can confirm this. This will be fixed in 2020.3.