Single Select not deleted the old values

[Денис Алексеенко (Nik ADA)]

Hi, community. I have strange behavior when I create AJS.SingleSelect

const options = {
    element: input,
    errorMessage: "",
    removeOnUnSelect: false,
    itemAttrDisplayed: "label",
    ajaxOptions: {
        url: AJS.contextPath() + "/rest/api/2/role",
        query: true,
        formatResponse: function (response) {
            let roles = [];
            response.forEach(function (role, i) {
                AJS.log(roles);
                AJS.log(i);
                let item = new AJS.ItemDescriptor({
                    value: role.id,
                    label: role.name,
                    title: role.name,
                    html: role.html,
                    highlighted: true
                });

                roles.push(item);
            });
            return roles;
        }
    }
};
new AJS.SingleSelect(options);

a Single Select is created, but when selecting values, the old values are not deleted

I tried change removeOnUnSelect from false to true but didn't help
But if I change /rest/api/2/role to /rest/api/2/project its work