diff --git a/translators/tmgmt_local/src/LocalTaskInterface.php b/translators/tmgmt_local/src/LocalTaskInterface.php
index 0484ce5..ad7c4a3 100644
--- a/translators/tmgmt_local/src/LocalTaskInterface.php
+++ b/translators/tmgmt_local/src/LocalTaskInterface.php
@@ -48,8 +48,8 @@ interface LocalTaskInterface extends ContentEntityInterface, EntityChangedInterf
   /**
    * Return the user assigned to this task.
    *
-   * @return \Drupal\Core\Session\AccountInterface
-   *   The user assigned to this task.
+   * @return \Drupal\Core\Session\AccountInterface|NULL
+   *   The user assigned to this task or NULL if there is no user assigned.
    */
   public function getAssignee();
 
diff --git a/translators/tmgmt_local/src/Tests/LocalTranslatorTest.php b/translators/tmgmt_local/src/Tests/LocalTranslatorTest.php
index efd7f67..a621038 100755
--- a/translators/tmgmt_local/src/Tests/LocalTranslatorTest.php
+++ b/translators/tmgmt_local/src/Tests/LocalTranslatorTest.php
@@ -367,6 +367,22 @@ class LocalTranslatorTest extends LocalTranslatorTestBase {
     $this->drupalGet('translate/items/' . $first_task_item->id());
     $this->assertResponse(403);
 
+    $this->drupalLogin($this->admin_user);
+
+    // Unassign the task.
+    $this->drupalGet('translate/' . $task->id());
+    $edit = [
+      'tuid' => '',
+    ];
+    $this->drupalPostForm(NULL, $edit, t('Save task'));
+    $this->clickLink(t('View'));
+
+    // Assign again the task to himself.
+    $edit = [
+      'tuid' => $this->assignee->id(),
+    ];
+    $this->drupalPostForm(NULL, $edit, t('Save task'));
+
     $this->drupalLogin($this->assignee);
 
     // Translate the task.