Call super.addProperties was missing.

ccm-cms/src/main/java/org/librecms/pages/models/RelatedLinkModelBuilder.java

@@ -51,6 +51,8 @@ public class RelatedLinkModelBuilder
     protected void addProperties(
         final RelatedLink relatedLink, final RelatedLinkModel model
     ) {
+        super.addProperties(relatedLink, model);
+        
         if (relatedLink.getBookmark() == null) {
             // Internal Link
             model.setExternalLink(false);