Undefined Index: search_restrict_type

Site migration time. An older site getting an upgrade (from Drupal 7.18, with Featured Content 7.x-1.5). I rebuilt the site in Drupal 7.37 (now 7.38) with the latest versions of all modules, but the following error message appears whenever I view content:

Notice: Undefined index: search_restrict_type in featured_content_get_filtered_nids() (line 1750 of {website}/sites/all/modules/featured_content/featured_content.module).

I get the same error message with Featured Content 7.x-1.x-dev. When I roll back to Featured Content 7.x-1.5, a different error appears:

Notice: Undefined property: stdClass::$rendered in featured_content_do_search() (line 2109 of {website}/sites/all/modules/featured_content/featured_content.module).

The current site does not have this problem. However, when I rebuild it as a Drupal 7.18 site, directly copying over all existing modules, the "Undefined property" error message appears. If I upgrade Featured Content to 7.x-1.6 in the Drupal 7.18 environment, the "Undefined index" error appears. Something of a head-scratcher.