diff --git a/runbot_merge/controllers/__init__.py b/runbot_merge/controllers/__init__.py
index cc0838bb..2e697589 100644
--- a/runbot_merge/controllers/__init__.py
+++ b/runbot_merge/controllers/__init__.py
@@ -157,6 +157,10 @@ vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
         )
 
 def handle_pr(env, event):
+    pr = event['pull_request']
+    squash = pr['commits'] == 1
+    r = pr['base']['repo']['full_name']
+
     if event['action'] in [
         'assigned', 'unassigned', 'review_requested', 'review_request_removed',
         'labeled', 'unlabeled'
@@ -167,14 +171,19 @@ def handle_pr(env, event):
             event['pull_request']['base']['repo']['full_name'],
             event['pull_request']['number'],
         )
+        if pr := env['runbot_merge.pull_requests'].search_fetch([
+            ('repository.name', '=', r),
+            ('number', '=', pr['number']),
+            ('squash', '!=', squash),
+        ]):
+            pr.squash = squash
+
         return Response(
             status=200,
             mimetype="text/plain",
             response="Not setup to receive action.",
         )
 
-    pr = event['pull_request']
-    r = pr['base']['repo']['full_name']
     b = pr['base']['ref']
 
     repo = env['runbot_merge.repository'].search([('name', '=', r)])
@@ -234,7 +243,7 @@ def handle_pr(env, event):
         if source_branch != branch:
             if branch != pr_obj.target:
                 updates['target'] = branch.id
-                updates['squash'] = pr['commits'] == 1
+                updates['squash'] = squash
 
         if 'title' in event['changes'] or 'body' in event['changes']:
             updates['message'] = utils.make_message(pr)
@@ -330,7 +339,7 @@ def handle_pr(env, event):
             pr_obj.head,
             pr['head']['sha'],
             event['sender']['login'],
-            pr['commits'] == 1
+            squash,
         )
         if pr['base']['ref'] != pr_obj.target.name:
             env['runbot_merge.fetch_job'].create({
@@ -343,10 +352,14 @@ def handle_pr(env, event):
             'reviewed_by': False,
             'error': False,
             'head': pr['head']['sha'],
-            'squash': pr['commits'] == 1,
+            'squash': squash,
         })
         return Response(mimetype="text/plain", response=f'Updated to {pr_obj.head}')
 
+    if event['action'] not in ('closed', 'reopened'):
+        if pr_obj.squash != squash:
+            pr_obj.squash = squash
+
     if event['action'] == 'ready_for_review':
         pr_obj.draft = False
         return Response(mimetype="text/plain", response=f'Updated {pr_obj.display_name} to ready')
diff --git a/runbot_merge/data/merge_cron.xml b/runbot_merge/data/merge_cron.xml
index a728acc5..b780e11c 100644
--- a/runbot_merge/data/merge_cron.xml
+++ b/runbot_merge/data/merge_cron.xml
@@ -65,6 +65,17 @@
     <field name="doall" eval="False"/>
     <field name="priority">50</field>
   </record>
+  <record model="ir.cron" id="check_merge_method">
+    <field name="name">Warn on PRs which are approved and have no merge method or squash</field>
+    <field name="model_id" ref="model_runbot_merge_pull_requests"/>
+    <field name="state">code</field>
+    <field name="code">model._check_merge_method_configuration(True)</field>
+    <field name="interval_number">6</field>
+    <field name="interval_type">hours</field>
+    <field name="numbercall">-1</field>
+    <field name="doall" eval="False"/>
+    <field name="priority">50</field>
+  </record>
   <record model="ir.cron" id="process_updated_commits">
     <field name="name">Impact commit statuses on PRs and stagings</field>
     <field name="model_id" ref="model_runbot_merge_commit"/>
diff --git a/runbot_merge/models/pull_requests.py b/runbot_merge/models/pull_requests.py
index 85c2b9d1..1012f281 100644
--- a/runbot_merge/models/pull_requests.py
+++ b/runbot_merge/models/pull_requests.py
@@ -893,7 +893,7 @@ For your own safety I've ignored *everything in your entire comment*.
                     self.batch_id.skipchecks = True
                     self.reviewed_by = author
                     if not (self.squash or self.merge_method):
-                        self.env.ref('runbot_merge.check_linked_prs_status')._trigger()
+                        self.env.ref('runbot_merge.check_merge_method')._trigger()
 
                     for p in self.batch_id.prs - self:
                         if not p.reviewed_by:
@@ -1165,7 +1165,7 @@ For your own safety I've ignored *everything in your entire comment*.
                 format_args={'user': login, 'pr': self},
             )
         if not (self.squash or self.merge_method):
-            self.env.ref('runbot_merge.check_linked_prs_status')._trigger()
+            self.env.ref('runbot_merge.check_merge_method')._trigger()
         return None
 
     def _pr_acl(self, user) -> ACL:
@@ -1516,6 +1516,7 @@ For your own safety I've ignored *everything in your entire comment*.
                 if commit:
                     self.env.cr.commit()
 
+    def _check_merge_method_configuration(self, commit=False):
         # send feedback for multi-commit PRs without a merge_method (which
         # we've not warned yet)
         methods = ''.join(