worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/heightmap/HeightmapProcessor.java

@@ -12,8 +12,6 @@ import com.sk89q.worldedit.world.block.BlockTypesCache;
 
 import javax.annotation.Nullable;
 import java.util.Arrays;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.Future;
 
 public class HeightmapProcessor implements IBatchProcessor {
 
@@ -25,7 +23,7 @@ public class HeightmapProcessor implements IBatchProcessor {
 
     static {
         Arrays.fill(COMPLETE, true);
-        Arrays.fill(AIR_LAYER, (char) 1);
+        Arrays.fill(AIR_LAYER, (char) BlockTypesCache.ReservedIDs.AIR);
     }
 
     private final int minY;

worldedit-core/src/main/java/com/fastasyncworldedit/core/history/changeset/AbstractChangeSet.java

@@ -179,14 +179,14 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
                 for (int z = 0; z < 16; z++) {
                     int zz = z + bz;
                     for (int x = 0; x < 16; x++, index++) {
-                        int xx = bx + x;
-                        int from = blocksGet[index];
-                        if (from == BlockTypesCache.ReservedIDs.__RESERVED__) {
-                            from = BlockTypesCache.ReservedIDs.AIR;
-                        }
-                        final int combinedFrom = from;
                         final int combinedTo = blocksSet[index];
                         if (combinedTo != BlockTypesCache.ReservedIDs.__RESERVED__) {
+                            int xx = bx + x;
+                            int from = blocksGet[index];
+                            if (from == BlockTypesCache.ReservedIDs.__RESERVED__) {
+                                from = BlockTypesCache.ReservedIDs.AIR;
+                            }
+                            final int combinedFrom = from;
                             add(xx, yy, zz, combinedFrom, combinedTo);
                         }
                     }