Looks to me like to me like this was a problem in 4.7.20 and 4.7.21 and am picking [this JIRA issue][1] is involved and have created [this JIRA issue][2] for the fix.


  [1]: https://issues.civicrm.org/jira/browse/CRM-15067
  [2]: http://%20https://issues.civicrm.org/jira/browse/CRM-20834