[рони]

dvbshka,
пробуйте ...

let timer, show = false;
            $("body").on('scroll', function() {
                window.clearTimeout(timer);
                if (!show) {
                    $("[message_sent_on]").each(function(i, el) {
                        let message_sent_on = el.getAttribute("message_sent_on");
                        el.querySelector("span").textContent = message_sent_on;
                        $(el).show();
                    })
                    show = true;
                }
                timer = window.setTimeout(function() {
                    $("[message_sent_on]").hide();
                    show = false;
                }, 100)
            })