Zombie Horse Jockey Spawn at light levels under 7

Zombie Horse Jockeys spawn on the surface during nighttime in Minecraft. However, because Zombie Horses are classified as passive mobs, they can spawn even if the light level is above 0 (they should only spawn at 0 light levels). What makes them dangerous is that Jockeys are counted as passengers. This has happened to Zombie Camel Jockeys.