Plugins Area on "[Plugin: Booking Ultra Pro Appointments Plugin] BUG: Choosing Business Hours Bad javascript"

Everytime you select a start time for business hours it hides the end time.

admin/scripts/admin.js
Your bug is in this function, please review

var $form   = $('#business-hours');
                jQuery(document).on("click", ".bup_select_start", function(e) {
                //$('.bup_select_start').on('change', function () {

                        var $row = $(this).parent(),
                                $end_select = $('.bup_select_end', $row),
                                $start_select = $(this);

                        if ($start_select.val()) {
                                $end_select.show();
                                $('span', $row).show();

                                var start_time = $start_select.val();

                                $('span > option', $end_select).each(function () {
                                        $(this).unwrap();
                                });

                                // Hides end time options with value less than in the start time
                                $('option', $end_select).each(function () {
                                        if ($(this).val() <= start_time) {
                                                $(this).wrap("<span>").parent().hide();
                                        }
                                });

                                if (start_time >= $end_select.val()) {
                                        $('option:visible:first', $end_select).attr('selected', true);
                                }
                        } else { // OFF

                                $end_select.hide();
                                $('span', $row).hide();
                        }
                }).each(function () {
                        var $row = $(this).parent(),
                                $end_select = $('.bup_select_end', $row);

                        $(this).data('default_value', $(this).val());
                        $end_select.data('default_value', $end_select.val());

                        // Hides end select for "OFF" days
                        if (!$(this).val()) {
                                $end_select.hide();
                                $('span', $row).hide();
                        }
                }).trigger('change');

https://wordpress.org/plugins/booking-ultra-pro/