diff --git a/modules/search_api_pantheon_admin/src/Form/PantheonSolrAdminForm.php b/modules/search_api_pantheon_admin/src/Form/PantheonSolrAdminForm.php
index 6773cbdc..709e1cc7 100644
--- a/modules/search_api_pantheon_admin/src/Form/PantheonSolrAdminForm.php
+++ b/modules/search_api_pantheon_admin/src/Form/PantheonSolrAdminForm.php
@@ -79,6 +79,10 @@ public function buildForm(
             '#group' => 'status',
             '#weight' => substr($filename, 0, -3) === 'xml' ? -10 : 10,
         ];
+
+      if ( ! is_string($file_contents)) {
+        $file_contents = json_encode($file_contents);
+      }
       $form[$filename][] = $this->getViewSolrFile($filename, $file_contents, $is_open);
       $is_open = FALSE;
     }