diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
index 4ec870d9d..fb4e263e0 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
@@ -1211,15 +1211,40 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
     private void updateAssignments(AllocationInterval interval,
             List<T> assignmentsCreated) {
 
+        /*
+         * removes assignments except those that are consolidated
+         */
         removingAssignments(withoutConsolidated(interval
                 .getAssignmentsOnInterval()));
-        addingAssignments(assignmentsCreated);
+        /*
+         * add the assignments except those that already are consolidated. At
+         * this moment all the assignments in the interval are consolidated. So
+         * that it removes the created assignments that have got same date and
+         * therefore are already added.
+         */
+        addingAssignments(subtractAssignmentsWithSameDate(assignmentsCreated,
+                interval.getAssignmentsOnInterval()));
 
         updateConsolidatedAssignments(interval);
         updateOriginalTotalAssigment();
         updateResourcesPerDay();
     }
 
+    private Collection<? extends T> subtractAssignmentsWithSameDate(
+            List<T> assignmentsCreated,
+            List<DayAssignment> assignmentsOnInterval) {
+        List<T> toRemove = new ArrayList<T>();
+        for (DayAssignment each : assignmentsOnInterval) {
+            for (T assignment : assignmentsCreated) {
+                if (each.getDay().compareTo(assignment.getDay()) == 0) {
+                    toRemove.add(assignment);
+                }
+            }
+        }
+        assignmentsCreated.removeAll(toRemove);
+        return assignmentsCreated;
+    }
+
     private void updateConsolidatedAssignments(AllocationInterval interval) {
         for (DayAssignment day : interval.getAssignmentsOnInterval()) {
             day.setConsolidated(false);