Autocomplete js - The list's scrollbar's list down arrow flickers

I have an autocomplete list and the list's scrollbar's down arrow is setting focus to first element, it flickers. While scrolling with mouse is working fine. Using jquery 3.4.1.

 .ui-autocomplete {
     position: absolute;
     top: 0;
     left: 0;
     cursor: default;
  }

The issue is only bottom arrow in auto complete list scroll bars:

from Autocomplete js - The list's scrollbar's list down arrow flickers