Add a material to check if air is air, because there are now 3 types of air.

worldedit-core/src/main/java/com/sk89q/worldedit/extent/world/SurvivalModeExtent.java

@@ -81,7 +81,7 @@ public class SurvivalModeExtent extends AbstractDelegateExtent {
 
     @Override
     public boolean setBlock(Vector location, BlockStateHolder block) throws WorldEditException {
-        if (toolUse && block.getBlockType() == BlockTypes.AIR) {
+        if (toolUse && block.getBlockType().getMaterial().isAir()) {
             world.simulateBlockMine(location);
             return true;
         } else {