After submit/complete form, unable proceed to completion

Hi, i facing a problem when Approver try to complete the form, but unable proceed to completion, after click "Confirm", then the screen keep loading there for more than an hours. (Only happen to certain request, but after resubmit a new request with all same info, the process go thru without issue)

var approve_confirmation = function() {

var aa = FormUtil.getField("status");

$(aa).val("Pending Approver");

console.log("aa " + $(aa).val());

$('#assignmentComplete').trigger("click");

}

$('#approve_confirmation').on('click', approve_confirmation);

i can see in the console that for that aa and its value.

There is no any log can be found in the tomcat log for this action.

How can i trouble shoot this kind of problem?