diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java
index cfb04ecbe..8ab979612 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java
@@ -171,9 +171,9 @@ public class Order extends OrderLineGroup {
                 deepCopyWithNeededReplaces(newOrderVersion),
                 newOrderVersion);
         useSchedulingDataFor(currentScenario);
+        removeSpuriousDayAssignments(currentScenario);
     }
 
-
     private DeepCopy deepCopyWithNeededReplaces(
             OrderVersion newOrderVersion) {
         DeepCopy result = new DeepCopy();
@@ -511,5 +511,4 @@ public class Order extends OrderLineGroup {
     public void setOrderVersion(Scenario scenario, OrderVersion newOrderVersion) {
         scenarios.put(scenario, newOrderVersion);
     }
-
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java
index 8c38ddf18..496bca253 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java
@@ -31,6 +31,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.Map.Entry;
 
 import org.apache.commons.lang.Validate;
 import org.hibernate.validator.AssertTrue;
@@ -63,6 +64,7 @@ import org.navalplanner.business.requirements.entities.CriterionRequirement;
 import org.navalplanner.business.requirements.entities.DirectCriterionRequirement;
 import org.navalplanner.business.requirements.entities.IndirectCriterionRequirement;
 import org.navalplanner.business.scenarios.entities.OrderVersion;
+import org.navalplanner.business.scenarios.entities.Scenario;
 import org.navalplanner.business.templates.entities.OrderElementTemplate;
 import org.navalplanner.business.trees.ITreeNode;
 import org.navalplanner.business.util.deepcopy.DeepCopy;
@@ -216,6 +218,32 @@ public abstract class OrderElement extends IntegrationEntity implements
         writeSchedulingDataChanges();
     }
 
+    protected void removeSpuriousDayAssignments(Scenario scenario) {
+        removeAtNotCurrent(scenario);
+        removeAtCurrent(scenario);
+        for (OrderElement each : getChildren()) {
+            each.removeSpuriousDayAssignments(scenario);
+        }
+    }
+
+    private void removeAtNotCurrent(Scenario scenario) {
+        SchedulingDataForVersion currentDataForVersion = getCurrentSchedulingDataForVersion();
+        for (Entry<OrderVersion, SchedulingDataForVersion> each : schedulingDatasForVersion
+                .entrySet()) {
+            SchedulingDataForVersion dataForVersion = each.getValue();
+            if (!currentDataForVersion.equals(dataForVersion)) {
+                dataForVersion.removeSpuriousDayAssignments(scenario);
+            }
+        }
+    }
+
+    private void removeAtCurrent(Scenario scenario) {
+        TaskElement associatedTaskElement = getAssociatedTaskElement();
+        if (associatedTaskElement != null) {
+            associatedTaskElement.removePredecessorsDayAssignmentsFor(scenario);
+        }
+    }
+
     public List<TaskSourceSynchronization> calculateSynchronizationsNeeded() {
         SchedulingDataForVersion schedulingDataForVersion = getCurrentSchedulingData()
                 .getVersion();
@@ -771,6 +799,12 @@ public abstract class OrderElement extends IntegrationEntity implements
         return result;
     }
 
+    public List<TaskSource> getAllScenariosTaskSourcesFromBottomToTop() {
+        List<TaskSource> result = new ArrayList<TaskSource>();
+        allScenariosTaskSourcesFromBottomToTop(result);
+        return result;
+    }
+
     public List<SchedulingDataForVersion> getSchedulingDatasForVersionFromBottomToTop() {
         List<SchedulingDataForVersion> result = new ArrayList<SchedulingDataForVersion>();
         schedulingDataForVersionFromBottomToTop(result);
@@ -794,6 +828,19 @@ public abstract class OrderElement extends IntegrationEntity implements
         }
     }
 
+    private void allScenariosTaskSourcesFromBottomToTop(List<TaskSource> result) {
+        for (OrderElement each : getChildren()) {
+            each.allScenariosTaskSourcesFromBottomToTop(result);
+        }
+        for (Entry<OrderVersion, SchedulingDataForVersion> each : schedulingDatasForVersion
+                .entrySet()) {
+            TaskSource taskSource = each.getValue().getTaskSource();
+            if (taskSource != null) {
+                result.add(taskSource);
+            }
+        }
+    }
+
     @Valid
     public Set<MaterialAssignment> getMaterialAssignments() {
         return Collections.unmodifiableSet(materialAssignments);
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/SchedulingDataForVersion.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/SchedulingDataForVersion.java
index b797a61d9..8156bfd22 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/SchedulingDataForVersion.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/SchedulingDataForVersion.java
@@ -25,7 +25,9 @@ import org.hibernate.validator.Valid;
 import org.navalplanner.business.common.BaseEntity;
 import org.navalplanner.business.orders.entities.SchedulingState.ITypeChangedListener;
 import org.navalplanner.business.orders.entities.SchedulingState.Type;
+import org.navalplanner.business.planner.entities.TaskElement;
 import org.navalplanner.business.scenarios.entities.OrderVersion;
+import org.navalplanner.business.scenarios.entities.Scenario;
 import org.navalplanner.business.util.deepcopy.DeepCopy;
 
 /**
@@ -179,4 +181,12 @@ public class SchedulingDataForVersion extends BaseEntity {
         return Data.from(this, orderVersion);
     }
 
+    void removeSpuriousDayAssignments(Scenario scenario) {
+        TaskSource taskSource = getTaskSource();
+        if (taskSource != null) {
+            TaskElement task = taskSource.getTask();
+            task.removeDayAssignmentsFor(scenario);
+        }
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedAllocation.java
index 5e3a4ab39..bdcca78fa 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedAllocation.java
@@ -362,4 +362,21 @@ public class DerivedAllocation extends BaseEntity {
         toContainer.resetAssignmentsTo(fromContainer.getDayAssignments());
     }
 
+    public void removePredecessorContainersFor(Scenario scenario) {
+        Map<Scenario, DerivedDayAssignmentsContainer> byScenario = byScenario();
+        for (Scenario each : scenario.getPredecessors()) {
+            DerivedDayAssignmentsContainer container = byScenario.get(each);
+            if (container != null) {
+                derivedDayAssignmentsContainers.remove(container);
+            }
+        }
+    }
+
+    public void removeContainersFor(Scenario scenario) {
+        DerivedDayAssignmentsContainer container = byScenario().get(scenario);
+        if (container != null) {
+            derivedDayAssignmentsContainers.remove(container);
+        }
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/GenericResourceAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/GenericResourceAllocation.java
index 2dcc911a5..eedf5dc6c 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/GenericResourceAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/GenericResourceAllocation.java
@@ -512,4 +512,24 @@ public class GenericResourceAllocation extends
         toContainer.resetTo(fromContainer.getDayAssignments());
     }
 
+    @Override
+    protected void removePredecessorContainersFor(Scenario scenario) {
+        Map<Scenario, GenericDayAssignmentsContainer> byScenario = containersByScenario();
+        for (Scenario each : scenario.getPredecessors()) {
+            GenericDayAssignmentsContainer container = byScenario.get(each);
+            if (container != null) {
+                genericDayAssignmentsContainers.remove(container);
+            }
+        }
+    }
+
+    @Override
+    protected void removeContainersFor(Scenario scenario) {
+        GenericDayAssignmentsContainer container = containersByScenario().get(
+                scenario);
+        if (container != null) {
+            genericDayAssignmentsContainers.remove(container);
+        }
+    }
+
 }
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 01f725718..47a8fabb7 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
@@ -1088,4 +1088,22 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
 
     public abstract void makeAssignmentsContainersDontPoseAsTransientAnyMore();
 
+    public void removePredecessorsDayAssignmentsFor(Scenario scenario) {
+        for (DerivedAllocation each : getDerivedAllocations()) {
+            each.removePredecessorContainersFor(scenario);
+        }
+        removePredecessorContainersFor(scenario);
+    }
+
+    protected abstract void removePredecessorContainersFor(Scenario scenario);
+
+    public void removeDayAssigmentsFor(Scenario scenario) {
+        for (DerivedAllocation each : getDerivedAllocations()) {
+            each.removeContainersFor(scenario);
+        }
+        removeContainersFor(scenario);
+    }
+
+    protected abstract void removeContainersFor(Scenario scenario);
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/SpecificResourceAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/SpecificResourceAllocation.java
index 29d75e8fa..ca05054f9 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/SpecificResourceAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/SpecificResourceAllocation.java
@@ -405,4 +405,24 @@ public class SpecificResourceAllocation extends
         toContainer.resetTo(fromContainer.getDayAssignments());
     }
 
+    @Override
+    protected void removePredecessorContainersFor(Scenario scenario) {
+        Map<Scenario, SpecificDayAssignmentsContainer> byScenario = containersByScenario();
+        for (Scenario each : scenario.getPredecessors()) {
+            SpecificDayAssignmentsContainer container = byScenario.get(each);
+            if (container != null) {
+                specificDayAssignmentsContainers.remove(container);
+            }
+        }
+    }
+
+    @Override
+    protected void removeContainersFor(Scenario scenario) {
+        SpecificDayAssignmentsContainer container = containersByScenario().get(
+                scenario);
+        if (container != null) {
+            specificDayAssignmentsContainers.remove(container);
+        }
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskElement.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskElement.java
index 2e4efa8ec..c6aa87e93 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskElement.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskElement.java
@@ -503,4 +503,16 @@ public abstract class TaskElement extends BaseEntity {
         return getEndDate().getTime() - getStartDate().getTime();
     }
 
+    public void removePredecessorsDayAssignmentsFor(Scenario scenario) {
+        for (ResourceAllocation<?> each : getAllResourceAllocations()) {
+            each.removePredecessorsDayAssignmentsFor(scenario);
+        }
+    }
+
+    public void removeDayAssignmentsFor(Scenario scenario) {
+        for (ResourceAllocation<?> each : getAllResourceAllocations()) {
+            each.removeDayAssigmentsFor(scenario);
+        }
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/scenarios/entities/Scenario.java b/navalplanner-business/src/main/java/org/navalplanner/business/scenarios/entities/Scenario.java
index 4dfb9609c..866f9daf4 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/scenarios/entities/Scenario.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/scenarios/entities/Scenario.java
@@ -120,6 +120,16 @@ public class Scenario extends BaseEntity {
         return predecessor;
     }
 
+    public List<Scenario> getPredecessors() {
+        List<Scenario> result = new ArrayList<Scenario>();
+        Scenario current = getPredecessor();
+        while (current != null) {
+            result.add(current);
+            current = current.getPredecessor();
+        }
+        return result;
+    }
+
     @AssertTrue(message = "name is already used")
     public boolean checkConstraintUniqueName() {
         if (StringUtils.isBlank(name)) {
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java
index 5b1d51756..d5483baf2 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java
@@ -490,6 +490,7 @@ public class OrderModel implements IOrderModel {
         if (newOrderVersionNeeded) {
             OrderVersion newVersion = OrderVersion
                     .createInitialVersion(currentScenario);
+            reattachAllTaskSources();
             order.writeSchedulingDataChangesTo(currentScenario, newVersion);
             createAndSaveNewOrderVersion(scenarioManager.getCurrent(),
                     newVersion);
@@ -556,6 +557,15 @@ public class OrderModel implements IOrderModel {
         }
     }
 
+    private void reattachAllTaskSources() {
+        // avoid LazyInitializationException for when doing
+        // removePredecessorsDayAssignmentsFor
+        for (TaskSource each : order
+                .getAllScenariosTaskSourcesFromBottomToTop()) {
+            taskSourceDAO.reattach(each);
+        }
+    }
+
     private void reattachTasksForTasksSources() {
         for (TaskSource each : order.getTaskSourcesFromBottomToTop()) {
             each.reloadTask(taskElementDAO);