Wardens listen to and are angered by underground mobs

i was experiencing the warden in the snap shot when i realised that its roaring at nothing and just ran to a place and only wander near there,and when i do spectator mode, i saw that there was a creeper and a zombie downthere,if this is a feature,plz improve the pathfinding ai,if its a bug,plz fix it to make the warden better