diff --git a/monitoring/db_update_sqlite.py b/monitoring/db_update_sqlite.py
index 7548c2c..bf90547 100644
--- a/monitoring/db_update_sqlite.py
+++ b/monitoring/db_update_sqlite.py
@@ -492,11 +492,16 @@ def refresh_gridsitesync_submithost():
             site = record.get("Site")
             month = record.get("Month")
             year = record.get("Year")
-            submit_host = record.get("SubmitHostSumm") or record.get("SubmitHostSync")
-            record_start = record.get("RecordStart")
+            # Use SubmitHostSync when SubmitHostSumm is missing (NaN)
+            submit_host = (
+                record.get("SubmitHostSync")
+                if pd.isna(record.get("SubmitHostSumm"))
+                else record.get("SubmitHostSumm")
+            )
+            record_start = none_if_missing(record.get("RecordStart"))
+            record_end = none_if_missing(record.get("RecordEnd"))
 
-            # Skip rows where RecordStart is missing or NaN
-            if pd.isna(record_start):
+            if pd.isna(submit_host):
                 continue
 
             # Sanitize numeric fields
@@ -516,7 +521,7 @@ def refresh_gridsitesync_submithost():
                 SubmitHost=submit_host,
                 defaults={
                     'RecordStart': record_start,
-                    'RecordEnd': record.get("RecordEnd"),
+                    'RecordEnd': record_end,
                     'RecordCountPublished': record_count_published,
                     'RecordCountInDb': record_count_in_db,
                 }
@@ -528,6 +533,13 @@ def refresh_gridsitesync_submithost():
         log.exception("Error while trying to refresh GridSiteSyncSubmitH")
 
 
+def none_if_missing(value):
+    """
+    Return None when the value is missing (NaN/NaT), otherwise return it unchanged.
+    """
+    return None if pd.isna(value) else value
+
+
 if __name__ == "__main__":
     log.info('=====================')
 
diff --git a/monitoring/publishing/models.py b/monitoring/publishing/models.py
index 195872d..27de057 100644
--- a/monitoring/publishing/models.py
+++ b/monitoring/publishing/models.py
@@ -86,8 +86,8 @@ class GridSiteSyncSubmitH(models.Model):
     YearMonth = models.CharField(max_length=255)
     Year = models.IntegerField()
     Month = models.IntegerField()
-    RecordStart = models.DateTimeField()
-    RecordEnd = models.DateTimeField()
+    RecordStart = models.DateTimeField(null=True)
+    RecordEnd = models.DateTimeField(null=True)
     RecordCountPublished = models.IntegerField()
     RecordCountInDb = models.IntegerField()
     SubmitHost = models.CharField(max_length=255)
diff --git a/monitoring/publishing/templates/gridsync_submithost.html b/monitoring/publishing/templates/gridsync_submithost.html
index 0baf9aa..d43d0f3 100644
--- a/monitoring/publishing/templates/gridsync_submithost.html
+++ b/monitoring/publishing/templates/gridsync_submithost.html
@@ -35,8 +35,8 @@ <h3>APEL Synchronisation Test</h3>
   <tr onmouseover="this.className='highlight-row'" onmouseout="this.className='tabletext'" class="tabletext">
     <td>{{ host.YearMonth }} </td>
     <td>{{ host.SubmitHost }}</td>
-    <td>{{ host.RecordStart }}</td>
-    <td>{{ host.RecordEnd }}</td>
+    <td>{{ host.RecordStart|default:"n/a" }}</td>
+    <td>{{ host.RecordEnd|default:"n/a" }}</td>
     <td>{{ host.RecordCountInDb|intcomma }}</td>
     <td>{{ host.RecordCountPublished|intcomma }}</td>
   </tr>