Ranger spells giving local echo even if no target

I can confirm that three ranger spells, available mostly to animists, give local echoes (to people other than the caster) even if there is not a legitimate target present. The spells I can confirm are: Swarm of Wasps Cloud of Mosquitoes Ancestral Spirit Trying to cast these spells on the target "nothing" will still result in everyone in the room seeing an echo, unlike other spells and communes that just fail.