Affirmatively check hireling entry instead of relying upon loadID =0 which was a side effect.

src/engine/objects/Mob.java

@@ -807,7 +807,8 @@ public class Mob extends AbstractIntelligenceAgent {
         // only if this building has a blueprint.
         // otherwise use the mob cache location.
 
-        if (this.building != null && building.getBlueprintUUID() != 0) {
+        if (this.building != null && building.getBlueprintUUID() != 0
+            && this.building.getHirelings().contains(this) == false) {
 
             int maxSlots = 10;