diff --git a/components/JsonToHtml/renderOptions.tsx b/components/JsonToHtml/renderOptions.tsx
index 7f8420bf6..5b4eda0d7 100644
--- a/components/JsonToHtml/renderOptions.tsx
+++ b/components/JsonToHtml/renderOptions.tsx
@@ -526,6 +526,8 @@ export const renderOptions: RenderOptions = {
   ) => {
     const props = extractPossibleAttributes(node.attrs)
 
+    props.className = props.className || ""
+
     if (props.className) {
       if (hasAvailableULFormat(props.className)) {
         // @ts-ignore:  We want to set css modules classNames even if it does not correspond
@@ -547,7 +549,7 @@ export const renderOptions: RenderOptions = {
       <ul
         key={node.uid}
         {...props}
-        className={`${styles.ul} ${props.className || ""}`}
+        className={`${styles.ul} ${props.className}`}
         style={
           numberOfRows
             ? {