CaseType.create - Stale definition retained in memory

If you modify the "definition" of a CaseType, the new definition doesn't fully take effect until a new page-request. For example, in this snippet, the timeline entry does not appear on the newly created case.

addToTimeline('housing_support', array('name' => 'Case Task', 'reference_activity' => 'Open Case', 'reference_offset' => '9', 'reference_select' => 'newest'));

civicrm_api3('Case', 'create', array(...'housing_support'...));

function addToTimeline($caseType, $timelineEntry) {
  $caseType = civicrm_api3('CaseType', 'getsingle', array('name' => $caseType));

  foreach ($caseType['definition']['activitySets'] as &$actSet) {
    if ($actSet['name'] === 'standard_timeline') {
      $actSet['activityTypes'][] = $timelineEntry;
      }
    }

  civicrm_api3('CaseType', 'create', array(
    'id' => $caseType['id'],
    'definition' => $caseType['definition'],
  ));
}