I guess that depends on what type of field you’re trying to change the choice labels on. Since you are running this on every field you need to check that it’s a field type that actually has choices, or make sure that choices is set.
if (!empty($field['choices'])) {
foreach ($field['choices'] as $value => $label) {
$field['choices'][$value] = WPGlobus_Core::text_filter($label, WPGlobus::Config()->language );
}
}