Upgrading for silver to diamond and gold to diamond are missing for the "Silver Silver Shulker Box". They exist in-game, but they're wrongly using the "Gray Silver Shulker Box".
So the recipes titled "shulker/gray/gold/silver_gold_shulker_box" and "shulker/silver/gold/silver_gold_shulker_box" are both using a gray box in the center. Same with respective silver to diamond recipes.
Upgrading for silver to diamond and gold to diamond are missing for the "Silver Silver Shulker Box". They exist in-game, but they're wrongly using the "Gray Silver Shulker Box".
So the recipes titled "shulker/gray/gold/silver_gold_shulker_box" and "shulker/silver/gold/silver_gold_shulker_box" are both using a gray box in the center. Same with respective silver to diamond recipes.