diff --git a/src/Bundle/ChillActivityBundle/Entity/Activity.php b/src/Bundle/ChillActivityBundle/Entity/Activity.php
index dba4f9c62..d77e0250b 100644
--- a/src/Bundle/ChillActivityBundle/Entity/Activity.php
+++ b/src/Bundle/ChillActivityBundle/Entity/Activity.php
@@ -230,45 +230,39 @@ class Activity implements AccompanyingPeriodLinkedWithSocialIssuesEntityInterfac
 
     public function addSocialAction(SocialAction $socialAction): self
     {
-        $descendants = $socialAction->getDescendantsWithThis();
-        $parent = $socialAction->getParent();
-
-        $parentKey = array_search($parent, $this->socialActions->toArray());
-
-        if (false !== $parentKey) {
-            $this->socialActions[$parentKey] = $socialAction;
-            // return $this;
+        if (!$this->socialActions->contains($socialAction)) {
+            $this->socialActions[] = $socialAction;
+            $this->ensureSocialActionConsistency();
         }
 
-        if (count($descendants) > 0) {
-            foreach ($descendants as $d) {
-                $inCollection = $this->socialActions->contains($d);
-                if ($inCollection) {
-                    return $this;
-                }
-            }
-        }
-
-        $this->socialActions[] = $socialAction;
         return $this;
     }
 
+    private function ensureSocialActionConsistency(): void
+    {
+        $ancestors = SocialAction::findAncestorSocialActions($this->getSocialActions());
+
+        foreach ($ancestors as $ancestor) {
+            $this->removeSocialAction($ancestor);
+        }
+    }
+
+    /**
+     * Add a social issue
+     *
+     * Note: the social issue consistency (the fact that only yougest social issues
+     * are kept) is processed by an entity listener:
+     * @see{\Chill\PersonBundle\AccompanyingPeriod\SocialIssueConsistency\AccompanyingPeriodSocialIssueConsistencyEntityListener}
+     *
+     * @param SocialIssue $socialIssue
+     * @return $this
+     */
     public function addSocialIssue(SocialIssue $socialIssue): self
     {
-        $descendants = $socialIssue->getDescendantsWithThis();
-
-        if (count($descendants) > 0) {
-            foreach ($descendants as $d) {
-                $inCollection = $this->socialIssues->contains($d);
-                if ($inCollection) {
-                    return $this;
-                }
-            }
+        if (!$this->socialIssues->contains($socialIssue)) {
+            $this->socialIssues[] = $socialIssue;
         }
 
-        $this->socialIssues[] = $socialIssue;
-
-
         return $this;
     }
 
diff --git a/src/Bundle/ChillActivityBundle/Tests/Entity/ActivityTest.php b/src/Bundle/ChillActivityBundle/Tests/Entity/ActivityTest.php
index c67c99894..a14ac4a24 100644
--- a/src/Bundle/ChillActivityBundle/Tests/Entity/ActivityTest.php
+++ b/src/Bundle/ChillActivityBundle/Tests/Entity/ActivityTest.php
@@ -12,12 +12,17 @@ declare(strict_types=1);
 namespace Chill\ActivityBundle\Tests\Entity;
 
 use Chill\ActivityBundle\Entity\Activity;
+use Chill\PersonBundle\AccompanyingPeriod\SocialIssueConsistency\AccompanyingPeriodSocialIssueConsistencyEntityListener;
+use Chill\PersonBundle\Entity\AccompanyingPeriod;
 use Chill\PersonBundle\Entity\SocialWork\SocialAction;
 use Chill\PersonBundle\Entity\SocialWork\SocialIssue;
+use Doctrine\ORM\Event\LifecycleEventArgs;
 use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
 
 final class ActivityTest extends TestCase
 {
+    use ProphecyTrait;
 
     public function testHierarchySocialActions(): void
     {
@@ -59,6 +64,9 @@ final class ActivityTest extends TestCase
 
     public function testHierarchySocialIssues(): void
     {
+        $listener = new AccompanyingPeriodSocialIssueConsistencyEntityListener();
+        $event = $this->prophesize(LifecycleEventArgs::class)->reveal();
+
         $parent = new SocialIssue();
         $child = new SocialIssue();
 
@@ -67,19 +75,23 @@ final class ActivityTest extends TestCase
         $child->addChild($grandChild);
 
         $activity = new Activity();
+        $activity->setAccompanyingPeriod(new AccompanyingPeriod());
 
         $activity->addSocialIssue($parent);
+        $listener->preUpdate($activity, $event);
 
         $this->assertCount(1, $activity->getSocialIssues());
         $this->assertContains($parent, $activity->getSocialIssues());
 
         $activity->addSocialIssue($grandChild);
+        $listener->preUpdate($activity, $event);
 
         $this->assertCount(1, $activity->getSocialIssues());
         $this->assertContains($grandChild, $activity->getSocialIssues());
         $this->assertNotContains($parent, $activity->getSocialIssues());
 
         $activity->addSocialIssue($child);
+        $listener->preUpdate($activity, $event);
 
         $this->assertCount(1, $activity->getSocialIssues());
         $this->assertContains($grandChild, $activity->getSocialIssues());
@@ -87,6 +99,7 @@ final class ActivityTest extends TestCase
         $this->assertNotContains($child, $activity->getSocialIssues());
 
         $activity->addSocialIssue($another = new SocialIssue());
+        $listener->preUpdate($activity, $event);
 
         $this->assertCount(2, $activity->getSocialIssues());
         $this->assertContains($grandChild, $activity->getSocialIssues());
@@ -95,4 +108,4 @@ final class ActivityTest extends TestCase
         $this->assertNotContains($child, $activity->getSocialIssues());
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/Bundle/ChillPersonBundle/Entity/SocialWork/SocialAction.php b/src/Bundle/ChillPersonBundle/Entity/SocialWork/SocialAction.php
index 01f30f140..198950494 100644
--- a/src/Bundle/ChillPersonBundle/Entity/SocialWork/SocialAction.php
+++ b/src/Bundle/ChillPersonBundle/Entity/SocialWork/SocialAction.php
@@ -307,4 +307,59 @@ class SocialAction
 
         return $this;
     }
+
+    /**
+     * Recursive method which return true if the current $action
+     * is a descendant of the $action given in parameter.
+     */
+    public function isDescendantOf(SocialAction $action): bool
+    {
+        if (!$this->hasParent()) {
+            return false;
+        }
+
+        if ($this->getParent() === $action) {
+            return true;
+        }
+
+        return $this->getParent()->isDescendantOf($action);
+    }
+
+    /**
+     * In a SocialIssues's collection, find the elements which are an ancestor of
+     * other elements.
+     *
+     * The difference of the given list (thus, the elements which are **not** kept
+     * in the returned collection) are the most-grand-child elements of the list.
+     *
+     * Removing those elements of the Collection (which is not done by this method)
+     * will ensure that only the most descendent elements are present in the collection,
+     * (any ancestor of another element are present).
+     *
+     * @param Collection|SocialAction[] $socialActions
+     *
+     * @return Collection|SocialAction[] a list with the elements of the given list which are parent of other elements in the given list
+     */
+    public static function findAncestorSocialActions(Collection $socialActions): Collection
+    {
+        $ancestors = new ArrayCollection();
+
+        foreach ($socialActions as $candidateChild) {
+            if ($ancestors->contains($candidateChild)) {
+                continue;
+            }
+
+            foreach ($socialActions as $candidateParent) {
+                if ($ancestors->contains($candidateParent)) {
+                    continue;
+                }
+
+                if ($candidateChild->isDescendantOf($candidateParent)) {
+                    $ancestors->add($candidateParent);
+                }
+            }
+        }
+
+        return $ancestors;
+    }
 }