Modified Bundle.js because of breaking Encoding.

Author: ulftietze

lib/internal/Magento/Framework/View/Asset/Bundle.php

@@ -212,7 +212,11 @@ protected function getAssetContent(LocalInterface $asset)
         $assetContentType = $asset->getContentType();
         $assetKey = $this->getAssetKey($asset);
         if (!isset($this->assetsContent[$assetContextCode][$assetContentType][$assetKey])) {
-            $this->assetsContent[$assetContextCode][$assetContentType][$assetKey] = utf8_encode($asset->getContent());
+            $content = $asset->getContent();
+            if (mb_detect_encoding($content) !== "UTF-8") {
+                $content = mb_convert_encoding($content, "UTF-8");
+            }
+            $this->assetsContent[$assetContextCode][$assetContentType][$assetKey] = $content;
         }
 
         return $this->assetsContent[$assetContextCode][$assetContentType][$assetKey];