Newly created revisions of previously published content have status = 1 set in node_revision table

I would think this is almost certainly due to this code in revisioning_node_presave().

  if (!empty($node->revision_moderation) && revisioning_user_may_auto_publish($node)) {
    revisioning_set_status_message(t('Auto-publishing this revision.'));
    // Follow the default saving process making this revision current and
    // published, as opposed to pending.
    unset($node->revision_moderation);
    // This is not required for correct operation, as a revision becomes
    // pending based on vid > current_revision_id. But it looks less confusing,
    // when the "Published" box is in sync with the moderation radio buttons.
    $node->status = NODE_PUBLISHED;
    $node->auto_publish = TRUE;
  } 

Hmmm, on second thought probably not as auto publish is turned off for this content type.

Possibly caused by

  if (isset($node->current_status)) {
    $node->status = $node->current_status; 
  }

in revisioning_node_update()?

Awesome that worked :)