diff --git a/backend/src/controllers/auth.controller.ts b/backend/src/controllers/auth.controller.ts
index bc6caac..29ef020 100644
--- a/backend/src/controllers/auth.controller.ts
+++ b/backend/src/controllers/auth.controller.ts
@@ -178,7 +178,7 @@ class AuthController {
           given_name:          updatedGivenName,
           family_name:         updatedFamilyName,
           preferred_username:  userInfo.preferred_username,
-          profile_picture_url: userInfo.picture || null,
+          profile_picture_url: userInfo.picture || undefined,
         });
 
         // Audit: returning user login