Minecraft wiki entry for Bastion_Remnant, associated text: Piglins, piglin brutes, and hoglins that spawn upon generation in bastion remnants neither despawn naturally, nor do they hunt each other. Piglin brutes also spawn exclusively here upon structure generation, and do not despawn unless killed, or if difficulty is set to Peaceful in Java Edition (they remain in Bedrock Edition but become passive in Peaceful difficulty). Like shulkers in end cities, once these mobs are killed, they do not respawn, though the bastion continues to spawn normal mobs depending on the biome it is located in.