diff --git a/docs/changes.rst b/docs/changes.rst
index 89b8e9d1c..7b99e403e 100644
--- a/docs/changes.rst
+++ b/docs/changes.rst
@@ -7,6 +7,9 @@ Changelog
 - Fix the i18n labels
   [ale-rt]
 
+- Fix the last modifier id for guest users that have been converted to registered users
+  [ale-rt]
+
 
 16.2.0 (2024-06-12)
 -------------------
diff --git a/src/euphorie/deployment/browser/maintenance.py b/src/euphorie/deployment/browser/maintenance.py
index dc12ebbb7..31f2b6d8e 100644
--- a/src/euphorie/deployment/browser/maintenance.py
+++ b/src/euphorie/deployment/browser/maintenance.py
@@ -2,6 +2,7 @@
 from euphorie.client.model import Session
 from euphorie.client.model import SurveySession
 from Products.Five import BrowserView
+from transaction import commit
 
 import logging
 
@@ -21,15 +22,19 @@ def __call__(self):
             .filter(Account.id != SurveySession.account_id)
             .filter(Account.account_type == "guest")
         )
-        for guest_user, assessment in obsolete_guest_users:
-            assessment.last_modifier_id = assessment.account_id
-            logger.info("Updated session %s", assessment.id)
-            num_assessments = (
-                session.query(SurveySession)
-                .filter(SurveySession.account_id == guest_user.id)
-                .count()
-            )
-            if num_assessments == 0:
-                session.delete(guest_user)
-                logger.info("Deleted user %s", guest_user.id)
+
+        with session.no_autoflush:
+            for guest_user, assessment in obsolete_guest_users:
+                assessment.last_modifier_id = assessment.account_id
+                logger.info("Updated session %s", assessment.id)
+
+                num_assessments = (
+                    session.query(SurveySession)
+                    .filter(SurveySession.account_id == guest_user.id)
+                    .count()
+                )
+                if num_assessments == 0:
+                    session.delete(guest_user)
+                    logger.info("Deleted user %s", guest_user.id)
+        commit()
         return "Done"