When Awakening Presence procs (10-30% chance to proc on minion death & it then casts Zombies for you), the Dreadful Horde (more Zombies per cast) & Giant Zombie (really big Zombie that does more damage/etc) nodes have only a 10% chance to be used instead of always being used. So 9 times out of 10 when Awakening Presence procs 'cause one of your minions died, you’ll get 1 normal Zombie instead of multiple Zombies or 1 big Zombie.
Same for the belt affix.