Bandit Mastery not working correctly

The bandit mastery claims to grant 3 gold (or 10 if melee) upon attacking an enemy champion with basic attack OR ABILITY. However, upon hitting an enemy champion WITH ABILITY, I do not get the 3, or 10 gold (depending on champion.) When auto attacking, it is very easy to see the gold being granted as it pops up above the enemies head. However, no such graphic happens upon landing an ability. So either the mastery does not grant the gold, or their is no graphic implemented to show the gold being granted for ability cast. Thank you.