I was playing around in an Ancient City when i activated a shrieker for a THIRD time, and not a fourth, but i heard a Warden Whining and saw it, the hitbox is glitched, I think the game was trying to play the emerge animation, because it was also invulnerable. The Warden isn't moving,

detecting sounds, or anything else, just stationary.

After about 2 minutes I heard the emerge sound while writing this and the Warden started moving, but still with a glitched hitbox and was still invulnerable. After another minute the Warden dug down and despawned like normal.