This is my code. The date input works and does register the dates, except when I try to add a date before 1905. When I save the taxonomy with this date 08/13/1899, I have an empty date field and my term meta is empty too. (but it work for 08/13/1980). The date picker does work and the date format is the good one…
add_action( 'cmb2_admin_init', 'details_taxonomy_metabox' );
function details_taxonomy_metabox() {
$cmb_term = new_cmb2_box( array(
'id' => 'taxonomy_details',
'title' => esc_html__( 'Taxomomy Details ', 'cmb2' ),
'object_types' => array( 'term' ),
'taxonomies' => array( 'authors' ),
) );
$cmb_term->add_field( array(
'name' => 'Date de naissance',
'id' => 'birth-date',
'type' => 'text_date',
) );
}