Unable to copy block nbt string to entity display name.

Custom loot table not copying nbt string to display name.
This setup outputs a blank display name ( {display:{Name:'

{"text":""}

'}} ) and was expecting the name to be "minecraft:pig".
Manually spawning the item works just fine.
/give @s minecraft:spawner{display:{Name:'

{"text":"minecraft:pig"}

'}}

File format attached: