diff --git a/conftest.py b/conftest.py
index e800258c..e7cdeda2 100644
--- a/conftest.py
+++ b/conftest.py
@@ -826,6 +826,12 @@ mutation setDraft($pid: ID!) {
     }
 }
 '''
+def state_prop(name: str) -> property:
+    @property
+    def _prop(self):
+        return self._pr[name]
+    return _prop.setter(lambda self, v: self._set_prop(name, v))
+
 class PR:
     def __init__(self, repo, number):
         self.repo = repo
@@ -850,15 +856,9 @@ class PR:
             caching['If-Modified-Since']= r.headers['Last-Modified']
         return contents
 
-    @property
-    def title(self):
-        return self._pr['title']
-    title = title.setter(lambda self, v: self._set_prop('title', v))
-
-    @property
-    def base(self):
-        return self._pr['base']
-    base = base.setter(lambda self, v: self._set_prop('base', v))
+    title = state_prop('title')
+    body = state_prop('body')
+    base = state_prop('base')
 
     @property
     def draft(self):
@@ -888,10 +888,6 @@ class PR:
     def state(self):
         return self._pr['state']
 
-    @property
-    def body(self):
-        return self._pr['body']
-
     @property
     def comments(self):
         r = self.repo._session.get('https://api.github.com/repos/{}/issues/{}/comments'.format(self.repo.name, self.number))
diff --git a/runbot_merge/changelog/2022-06/empty-body.md b/runbot_merge/changelog/2022-06/empty-body.md
new file mode 100644
index 00000000..093962f5
--- /dev/null
+++ b/runbot_merge/changelog/2022-06/empty-body.md
@@ -0,0 +1,4 @@
+FIX: correctly handle PR empty PR descriptions
+
+Github's webhook for this case are weird, and weren't handled correctly,
+updating a PR's description to *or from* empty might be mishandled.
diff --git a/runbot_merge/controllers/__init__.py b/runbot_merge/controllers/__init__.py
index ecee99f3..3b0b02c0 100644
--- a/runbot_merge/controllers/__init__.py
+++ b/runbot_merge/controllers/__init__.py
@@ -120,15 +120,25 @@ def handle_pr(env, event):
         if not source_branch:
             return handle_pr(env, dict(event, action='opened'))
 
+        pr_obj = find(source_branch)
         updates = {}
         if source_branch != branch:
-            updates['target'] = branch.id
-            updates['squash'] = pr['commits'] == 1
-        if event['changes'].keys() & {'title', 'body'}:
-            updates['message'] = "{}\n\n{}".format(pr['title'].strip(), pr['body'].strip())
+            if branch != pr_obj.target:
+                updates['target'] = branch.id
+                updates['squash'] = pr['commits'] == 1
+
+        # turns out github doesn't bother sending a change key if the body is
+        # changing from empty (None), therefore ignore that entirely, just
+        # generate the message and check if it changed
+        message = pr['title'].strip()
+        body = (pr['body'] or '').strip()
+        if body:
+            message += f"\n\n{body}"
+        if message != pr_obj.message:
+            updates['message'] = message
+
         _logger.info("update: %s#%d = %s (by %s)", repo.name, pr['number'], updates, event['sender']['login'])
         if updates:
-            pr_obj = find(source_branch)
             pr_obj.write(updates)
             return 'Updated {}'.format(pr_obj.id)
         return "Nothing to update ({})".format(event['changes'].keys())
diff --git a/runbot_merge/tests/test_basic.py b/runbot_merge/tests/test_basic.py
index 1f254960..5049fcda 100644
--- a/runbot_merge/tests/test_basic.py
+++ b/runbot_merge/tests/test_basic.py
@@ -728,6 +728,8 @@ class TestPREdition:
         assert pr.message == 'title\n\nbody'
         with repo: prx.title = "title 2"
         assert pr.message == 'title 2\n\nbody'
+        with repo: prx.body = None
+        assert pr.message == "title 2"
         assert pr.staging_id, \
             "message edition does not affect staging of rebased PRs"
         with repo: prx.base = '1.0'