I'm writing a small datapack and I've created a custom item called the Silver Ingot with multiple ways to obtain it: it can be crafted manually or obtained by killing a certain enemy.

The first method invokes a command, which sets its custom name using NBT data as follows:

{display:{Name:"

{\"text\":\"Silver Ingot\",\"italic\":\"false\"}

"}}

The second method uses custom loot tables, and since (as far as I'm aware) the {display} NBT tag can't be used with the set_nbt function in loot tables, I have to create the custom name like this:

"function": "set_name",
"name":

{ "text": "Silver Ingot", "italic": "false" }

Both of these methods create the items exactly as they should be, in that all their NBT data is the same and both can be used in the same custom crafting recipes. They're exactly the same. But for some reason, Silver Ingots obtained from crafting can't be stacked with those obtained from killing enemies, as if the game thinks they're different items. Turning Advanced Tooltips on even shows that everything about them is the same, so they're no reason the game should see them as different items and prevent them from being stacked with each other. This is basically the equivalent of getting wool from sheep, and then crafting wool with string, and being unable to stack the two pieces of wool you got.