This is the code that exhibits both issues: the title/menu switcharoo and the slug breaking my options page fields.
<?php
if( function_exists('acf_add_options_sub_page') )
{
acf_add_options_sub_page(array(
'title' => 'Mapping',
'menu' => 'Mapping Settings',
'parent' => 'options-general.php',
'slug' => 'mapping',
'capability' => 'manage_options'
));
}
?>
