diff --git a/src/Symfony/Component/Translation/Catalogue/TargetOperation.php b/src/Symfony/Component/Translation/Catalogue/TargetOperation.php
index 8221d184d2f89..c8b0655125321 100644
--- a/src/Symfony/Component/Translation/Catalogue/TargetOperation.php
+++ b/src/Symfony/Component/Translation/Catalogue/TargetOperation.php
@@ -49,7 +49,7 @@ protected function processDomain($domain)
         foreach ($this->source->all($domain) as $id => $message) {
             if ($this->target->has($id, $domain)) {
                 $this->messages[$domain]['all'][$id] = $message;
-                $d = $this->target->defines($id, $intlDomain) ? $intlDomain : $domain;
+                $d = $this->source->defines($id, $intlDomain) ? $intlDomain : $domain;
                 $this->result->add([$id => $message], $d);
                 if (null !== $keyMetadata = $this->source->getMetadata($id, $d)) {
                     $this->result->setMetadata($id, $keyMetadata, $d);
diff --git a/src/Symfony/Component/Translation/Tests/Catalogue/TargetOperationTest.php b/src/Symfony/Component/Translation/Tests/Catalogue/TargetOperationTest.php
index 354c213e9e3b7..d5441f3bee4ef 100644
--- a/src/Symfony/Component/Translation/Tests/Catalogue/TargetOperationTest.php
+++ b/src/Symfony/Component/Translation/Tests/Catalogue/TargetOperationTest.php
@@ -71,13 +71,45 @@ public function testGetResultWithMixedDomains()
     {
         $this->assertEquals(
             new MessageCatalogue('en', [
-                'messages+intl-icu' => ['a' => 'old_a'],
+                'messages' => ['a' => 'old_a'],
             ]),
             $this->createOperation(
                 new MessageCatalogue('en', ['messages' => ['a' => 'old_a']]),
                 new MessageCatalogue('en', ['messages+intl-icu' => ['a' => 'new_a']])
             )->getResult()
         );
+
+        $this->assertEquals(
+            new MessageCatalogue('en', [
+                'messages+intl-icu' => ['a' => 'old_a'],
+            ]),
+            $this->createOperation(
+                new MessageCatalogue('en', ['messages+intl-icu' => ['a' => 'old_a']]),
+                new MessageCatalogue('en', ['messages' => ['a' => 'new_a']])
+            )->getResult()
+        );
+
+        $this->assertEquals(
+            new MessageCatalogue('en', [
+                'messages+intl-icu' => ['a' => 'old_a'],
+                'messages' => ['b' => 'new_b'],
+            ]),
+            $this->createOperation(
+                new MessageCatalogue('en', ['messages+intl-icu' => ['a' => 'old_a']]),
+                new MessageCatalogue('en', ['messages' => ['a' => 'new_a', 'b' => 'new_b']])
+            )->getResult()
+        );
+
+        $this->assertEquals(
+            new MessageCatalogue('en', [
+                'messages' => ['a' => 'old_a'],
+                'messages+intl-icu' => ['b' => 'new_b'],
+            ]),
+            $this->createOperation(
+                new MessageCatalogue('en', ['messages' => ['a' => 'old_a']]),
+                new MessageCatalogue('en', ['messages+intl-icu' => ['a' => 'new_a', 'b' => 'new_b']])
+            )->getResult()
+        );
     }
 
     public function testGetResultWithMetadata()