The `below_name` plate of players and mannequins is hidden based on the three-dimensional distance to their feet position, causing it not to be visible when near the plate of scaled up ones

When near the top of a Mannequin that is sufficiently scaled, the NPC text doesn’t appear.

1. Run an attribute command that scales a Mannequin

   /attribute @n[type=mannequin] minecraft:scale base set 10

2. Fly near the Mannequin’s head

You’ll see the NPC text not show up.

If you change the scale to a smaller value like 5 for example, the NPC text shows no matter where you are if you’re near it.