self-signup enrollment flow not sending configured approval notification

A self-signup enrollment flow is configured to send email to the enrollee on approval, but the only email sent out to the enrollee is the default notification email (rs.pt.status).

The enrollment flow has this configuration:

MySQL [gw_astronomy_registry]> select * from cm_co_enrollment_flows where id = 213\G

• • • • • • • • • • • • • • • • • • • • • • • • • • • 1. row ***************************
                                                      id: 213
                                                      name: Self Signup With Approval
                                                      co_id: 17
                                                      authz_level: AU
                                                      authz_cou_id: NULL
                                                      authz_co_group_id: NULL
                                                      match_policy: N
                                                      approval_required: 1
                                                      verify_email: NULL
                                                      require_authn: 1
                                                      status: A
                                                      created: 2019-12-19 22:45:52
                                                      modified: 2019-12-21 01:02:16
                                                      notify_from:
                                                      verification_subject: Verify your email to join (@CO_NAME)
                                                      verification_body: You have requested to join (@CO_NAME).
                                                      Please click the link below to accept or decline. After you accept, the (@CO_NAME) administrators will review your request.

(@INVITE_URL)
notify_on_approval: 1
approval_subject: Petition to join (@CO_NAME) has been approved
approval_body: Your petition to join (@CO_NAME) as been approved.
introduction_text: Complete this form to join IGWN-DHTC-OSG. After you submit, you will receive an email with a link to confirm your email address. After you verify your email address, your petition to join will be submitted to the approvers. Please do not reapply or submit this form multiple times as this could cause a delay in approving your petition.
redirect_on_submit:
redirect_on_confirm:
approver_co_group_id: NULL
ignore_authoritative: 0
notification_co_group_id: 745
invitation_validity: 1440
conclusion_text: Thank you.
t_and_c_mode: X
duplicate_mode: D
co_enrollment_flow_id: NULL
revision: 16
deleted: 0
actor_identifier: http://cilogon.org/serverA/users/22981
co_pipeline_id: NULL
email_verification_mode: A
verification_template_id: NULL
approval_template_id: NULL
notify_on_finalize: 0
finalization_template_id: NULL
co_theme_id: NULL
redirect_on_finalize:
return_url_whitelist:
my_identity_shortcut: 0
1 row in set (0.00 sec)

The email the enrollee receives has body

Petition for Donald Koranda changed status from Pending Approval to Approved (Self Signup With Approval)

https://registry.gw-astronomy.org/registry/co_petitions/view/28621

For more information, see the notification at

https://registry.gw-astronomy.org/registry/co_notifications/view/7123
 
The enrollee should receive an email with the content from approval_body.