Mark CFP messages read before creating the reply (fixes #1646)

apps/cfp/views.py

@@ -854,6 +854,13 @@ def proposal_messages(proposal_id):
     form = MessagesForm()
 
     if form.validate_on_submit():
+        # The user is replying, mark any outstanding messages as read
+        count = proposal.mark_messages_read(current_user)
+        db.session.commit()
+        app.logger.info(
+            f"Marked {count} messages from admin on proposal {proposal.id} as read"
+        )
+
         if form.send.data:
             msg = CFPMessage()
             msg.is_to_admin = True
@@ -870,12 +877,6 @@ def proposal_messages(proposal_id):
                     f"✉️ New CfP message for {proposal.human_type}: {external_url('cfp_review.message_proposer', proposal_id=proposal_id)} ✉️",
                 )
 
-        count = proposal.mark_messages_read(current_user)
-        db.session.commit()
-        app.logger.info(
-            "Marked %s messages to admin on proposal %s as read" % (count, proposal.id)
-        )
-
         return redirect(url_for(".proposal_messages", proposal_id=proposal_id))
 
     messages = (