diff --git a/runbot_merge/controllers/__init__.py b/runbot_merge/controllers/__init__.py
index 49a6323b..3c15a50c 100644
--- a/runbot_merge/controllers/__init__.py
+++ b/runbot_merge/controllers/__init__.py
@@ -166,6 +166,16 @@ def handle_pr(env, event):
 
     # don't marked merged PRs as closed (!!!)
     if event['action'] == 'closed' and pr_obj.state != 'merged':
+        # ignore if the PR is already being updated in a separate transaction
+        # (most likely being merged?)
+        env.cr.execute('''
+        SELECT id FROM runbot_merge_pull_requests
+        WHERE id = %s AND state != 'merged'
+        FOR UPDATE SKIP LOCKED;
+        ''', [pr_obj.id])
+        if not env.cr.fetchall():
+            return 'Ignored: could not lock rows (probably being merged)'
+
         env.cr.execute('''
         UPDATE runbot_merge_pull_requests
         SET state = 'closed'
diff --git a/runbot_merge/data/merge_cron.xml b/runbot_merge/data/merge_cron.xml
index c3e225a3..091efa08 100644
--- a/runbot_merge/data/merge_cron.xml
+++ b/runbot_merge/data/merge_cron.xml
@@ -3,7 +3,7 @@
     <field name="name">Check for progress of PRs &amp; Stagings</field>
     <field name="model_id" ref="model_runbot_merge_project"/>
     <field name="state">code</field>
-    <field name="code">model._check_progress()</field>
+    <field name="code">model._check_progress(True)</field>
     <field name="interval_number">1</field>
     <field name="interval_type">minutes</field>
     <field name="numbercall">-1</field>
diff --git a/runbot_merge/models/pull_requests.py b/runbot_merge/models/pull_requests.py
index 4285e9bd..d1998fc0 100644
--- a/runbot_merge/models/pull_requests.py
+++ b/runbot_merge/models/pull_requests.py
@@ -61,13 +61,17 @@ class Project(models.Model):
              "will lead to webhook rejection. Should only use ASCII."
     )
 
-    def _check_progress(self):
+    def _check_progress(self, commit=False):
         for project in self.search([]):
             for staging in project.mapped('branch_ids.active_staging_id'):
                 staging.check_status()
+                if commit:
+                    self.env.cr.commit()
 
             for branch in project.branch_ids:
                 branch.try_staging()
+                if commit:
+                    self.env.cr.commit()
 
         # I have no idea why this is necessary for tests to pass, the only
         # DB update done not through the ORM is when receiving a notification