diff --git a/core/modules/locale/src/LocaleConfigSubscriber.php b/core/modules/locale/src/LocaleConfigSubscriber.php
index ee20daf..8a23ea1 100644
--- a/core/modules/locale/src/LocaleConfigSubscriber.php
+++ b/core/modules/locale/src/LocaleConfigSubscriber.php
@@ -82,7 +82,7 @@ public static function getSubscribedEvents() {
   public function onConfigSave(ConfigCrudEvent $event) {
     // Only attempt to feed back configuration translation changes to locale if
     // the update itself was not initiated by locale data changes.
-    if (!$this->localeConfigManager->isUpdatingTranslationsFromLocale()) {
+    if (!drupal_installation_attempted() && !$this->localeConfigManager->isUpdatingTranslationsFromLocale()) {
       $config = $event->getConfig();
       $langcode = $config->get('langcode') ?: 'en';
       $this->updateLocaleStorage($config, $langcode);
@@ -98,7 +98,7 @@ public function onConfigSave(ConfigCrudEvent $event) {
   public function onOverrideChange(LanguageConfigOverrideCrudEvent $event) {
     // Only attempt to feed back configuration override changes to locale if
     // the update itself was not initiated by locale data changes.
-    if (!$this->localeConfigManager->isUpdatingTranslationsFromLocale()) {
+    if (!drupal_installation_attempted() && !$this->localeConfigManager->isUpdatingTranslationsFromLocale()) {
       $translation_config = $event->getLanguageConfigOverride();
       $langcode = $translation_config->getLangcode();
       $reference_config = $this->configFactory->getEditable($translation_config->getName())->get();
@@ -204,23 +204,25 @@ protected function resetExistingTranslations($name, $translatable, $reference_co
    *   The source string value.
    * @param string $context
    *   The source string context.
-   * @param string $translation
+   * @param string $new_translation
    *   The translation string.
    * @param string $langcode
    *   The language code of the translation.
    */
-  protected function saveCustomizedTranslation($name, $source, $context, $translation, $langcode) {
+  protected function saveCustomizedTranslation($name, $source, $context, $new_translation, $langcode) {
     $locale_translation = $this->localeConfigManager->getStringTranslation($name, $langcode, $source, $context);
     if (!empty($locale_translation)) {
       // Save this translation as custom if it was a new translation and not the
       // same as the source. (The interface prefills translation values with the
-      // source). Or if there was an existing translation and the user changed
-      // it (even if it was changed back to the original value). Otherwise the
-      // translation file would be overwritten with the locale copy again later.
-      if (($locale_translation->isNew() && $source != $translation) ||
-          (!$locale_translation->isNew() && $translation != $locale_translation->getString())) {
+      // source). Or if there was an existing (non-empty) translation and the
+      // user changed it (even if it was changed back to the original value).
+      // Otherwise the translation file would be overwritten with the locale
+      // copy again later.
+      $existing_translation = $locale_translation->getString();
+      if (($locale_translation->isNew() && $source != $new_translation) ||
+        (!$locale_translation->isNew() && ((empty($existing_translation) && $source != $new_translation) || ((!empty($existing_translation) && $new_translation != $existing_translation))))) {
         $locale_translation
-          ->setString($translation)
+          ->setString($new_translation)
           ->setCustomized(TRUE)
           ->save();
       }
diff --git a/core/modules/system/src/Tests/Installer/InstallerTranslationMultipleLanguageTest.php b/core/modules/system/src/Tests/Installer/InstallerTranslationMultipleLanguageTest.php
index a16369b..a7051c7 100644
--- a/core/modules/system/src/Tests/Installer/InstallerTranslationMultipleLanguageTest.php
+++ b/core/modules/system/src/Tests/Installer/InstallerTranslationMultipleLanguageTest.php
@@ -53,6 +53,9 @@ protected function getPo($langcode) {
 
 msgid "Anonymous"
 msgstr "Anonymous $langcode"
+
+msgid "Language"
+msgstr "Language $langcode"
 ENDPO;
   }
 
@@ -75,19 +78,7 @@ public function testTranslationsLoaded() {
     }
 
     // Verify the strings from the translation files were imported.
-    $test_samples = ['Save and continue', 'Anonymous'];
-    $langcodes = ['de', 'es'];
-
-    foreach($test_samples as $sample) {
-      foreach($langcodes as $langcode) {
-        $edit = array();
-        $edit['langcode'] = $langcode;
-        $edit['translation'] = 'translated';
-        $edit['string'] = $sample;
-        $this->drupalPostForm('admin/config/regional/translate', $edit, t('Filter'));
-        $this->assertText($sample . ' ' . $langcode);
-      }
-    }
+    $this->verifyImportedStringsTranslated();
 
     /** @var \Drupal\language\ConfigurableLanguageManager $language_manager */
     $language_manager = \Drupal::languageManager();
@@ -127,6 +118,17 @@ public function testTranslationsLoaded() {
         $override_en = $language_manager->getLanguageConfigOverride('en', 'user.settings');
         $this->assertEqual($override_en->get('anonymous'), 'Anonymous');
       }
+
+      // Activate a module, to make sure that config is not overriden by module
+      // installation.
+      $edit = array(
+        'modules[Core][views][enable]' => TRUE,
+        'modules[Core][filter][enable]' => TRUE,
+      );
+      $this->drupalPostForm('admin/modules', $edit, t('Save configuration'));
+
+      // Verify the strings from the translation are still as expected.
+      $this->verifyImportedStringsTranslated();
     }
     else {
       // Active configuration should be English.
@@ -140,6 +142,26 @@ public function testTranslationsLoaded() {
 
     // Spanish is always an override (never used as installation language).
     $this->assertEqual($override_es->get('anonymous'), 'Anonymous es');
+
+  }
+
+  /**
+   * Helper function to verify that the expected strings are translated.
+   */
+  protected function verifyImportedStringsTranslated() {
+    $test_samples = ['Save and continue', 'Anonymous', 'Language'];
+    $langcodes = ['de', 'es'];
+
+    foreach($test_samples as $sample) {
+      foreach($langcodes as $langcode) {
+        $edit = array();
+        $edit['langcode'] = $langcode;
+        $edit['translation'] = 'translated';
+        $edit['string'] = $sample;
+        $this->drupalPostForm('admin/config/regional/translate', $edit, t('Filter'));
+        $this->assertText($sample . ' ' . $langcode);
+      }
+    }
   }
 
 }