How to Stop Spawner Shulkers From Respawning

Understand the default behavior

By default, shulkers that come from a mob spawner will not respawn after being killed. Only naturally spawned shulkers (the ones you find in End cities) return to their death location. This keeps spawner-based farms from becoming infinite shell machines.

Check the config toggle

Open the mod's config file and find shulkersFromSpawnersDoNotRespawn. When this is set to true, spawner shulkers stay dead permanently. If you want them to respawn like normal shulkers, flip it to false. Save the file and restart the world.

Verify with a test spawner

Place a shulker spawner in a controlled area, let it spawn a shulker, and kill it. If the toggle is true, no shulker should appear at the death spot. If it is false, one should return. This lets you confirm the setting is working before building a large farm around it. Remember that changing this affects every spawner shulker in the world, so decide based on whether you want a fair challenge or a fully automated shell source.