If you want to manage more than one tab, I used a unique function name for each instance:
add_filter('acf/prepare_field/key=field_key', 'custom_tab_format', 20);
function custom_tab_format($field) {
if(get_field('this_field', $post->ID)) {
$field['label'] = get_field('this_field', $post->ID);
}
return $field; }
add_filter('acf/prepare_field/key=field_key', 'custom_tab_format_two', 20);
function custom_tab_format_two($field) {
if(get_field('this_field', $post->ID)) {
$field['label'] = get_field('this_field', $post->ID);
}
return $field; }
Hopefully this is helpful to others.
