email verification email has empty body

I have this enrollment flow defined:

• • • • • • • • • • • • • • • • • • • • • • • • • • • 1. row ***************************
                                                      id: 1
                                                      name: basic LIGO IdMS enrollment
                                                      co_id: 2
                                                      authz_level: N
                                                      authz_cou_id: NULL
                                                      authz_co_group_id: NULL
                                                      match_policy: N
                                                      approval_required: 0
                                                      verify_email: 1
                                                      require_authn: 0
                                                      early_provisioning_exec: NULL
                                                      provisioning_exec: NULL
                                                      notify_on_early_provision: NULL
                                                      notify_on_provision: NULL
                                                      notify_on_active: NULL
                                                      status: A
                                                      notify_from: ligo-identity-system@ligo.org
                                                      verification_subject: your LIGO identity request action required
                                                      verification_body: Please click here to confirm the email address you submitted when requesting a LIGO identity.

(@INVITE_URL)
notify_on_approval: 0
approval_subject: Petition to join (@CO_NAME) has been approved
approval_body: Your petition to join (@CO_NAME) as been approved. You may now log in to the platform.
introduction_text: Complete this form to create a new LIGO identity and continue requesting joining a LIGO collaboration group including the LIGO Laboratory, the LIGO Scientific Collaboration (LSC), or Virgo.
created: 2013-10-07 22:25:12
modified: 2013-10-09 15:47:29
redirect_on_submit:
redirect_on_confirm:

When a new enrollment happens the email received has the configured subject but the message body is empty.