Despawn component not functional for custom mobs

Custom mobs do not seem to despawn from any distance with the "despawn" component, I also noticed this occurs with other popular addons.

This is the code included in the JSON behavior file, in the mobs' components.
 

 
Expectation:
Custom mobs with this component should despawn when all players are far enough from the mob.
 
Result:
Custom mobs with this component do not despawn seemingly forever.