diff --git a/repository/src/main/java/org/alfresco/repo/site/SiteMembership.java b/repository/src/main/java/org/alfresco/repo/site/SiteMembership.java
index 0d316041ac..efbe210d6a 100644
--- a/repository/src/main/java/org/alfresco/repo/site/SiteMembership.java
+++ b/repository/src/main/java/org/alfresco/repo/site/SiteMembership.java
@@ -78,7 +78,7 @@ public class SiteMembership extends AbstractSiteMembership
                     "FirstName required building site membership of " + siteInfo.getShortName());
         }
         this.firstName = firstName;
-        this.lastName = Optional.of(lastName).orElse("");
+        this.lastName = Optional.ofNullable(lastName).orElse("");
         this.isMemberOfGroup = isMemberOfGroup;
     }