diff --git a/packages/string-templates/src/helpers/date.js b/packages/string-templates/src/helpers/date.js
index 27554d1d9e..6fe8b288d6 100644
--- a/packages/string-templates/src/helpers/date.js
+++ b/packages/string-templates/src/helpers/date.js
@@ -115,7 +115,7 @@ module.exports.duration = (str, pattern, format) => {
   setLocale(config.str, config.pattern)
 
   const duration = dayjs.duration(config.str, config.pattern)
-  if (!isOptions(format)) {
+  if (format && !isOptions(format)) {
     return duration.format(format)
   } else {
     return duration.humanize()
diff --git a/packages/string-templates/src/helpers/list.js b/packages/string-templates/src/helpers/list.js
index 6d5241cdd8..92f5ee03ce 100644
--- a/packages/string-templates/src/helpers/list.js
+++ b/packages/string-templates/src/helpers/list.js
@@ -27,6 +27,7 @@ module.exports.getHelperList = () => {
   return helpers
 }
 
+// Some helpers depend on handlebars injecting some parameters. This function adjust the helpers when required
 function adjustJsHelpers(helpers) {
   const result = { ...helpers }