Add Check

src/main/java/com/thebrokenrail/energonrelics/block/structure/StructureGeneratorBlock.java

@@ -100,8 +100,10 @@ public class StructureGeneratorBlock extends SimpleBlockWithEntity {
     @Override
     public void onBlockAdded(BlockState state, World world, BlockPos pos, BlockState oldState, boolean notify) {
         super.onBlockAdded(state, world, pos, oldState, notify);
+        if (world instanceof ServerWorld) {
             schedule(world, pos);
         }
+    }
 
     public void schedule(World world, BlockPos pos) {
         world.getBlockTickScheduler().schedule(pos, this, 0);