$(document).on('mouseenter', '.select2-selection__rendered', function () {
var tooltipId = $(this).attr("aria-describedby"); // contains the id of the tooltip
$("#" + tooltipId).hide(); // hide the tooltip before it fades in
$(this).unbind('mouseenter mouseleave'); // stop it showing another tooltip
});

  <style>
  .ui-autocomplete {
  position: absolute;
  z-index: 99999 !important;
  cursor: default;
  padding: 0;
  margin-top: 2px;
  list-style: none;
  background-color: #ffffff;
  border: 1px solid #ccc -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  border-radius: 5px;
  -webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
  -moz-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
  box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
}

.ui-autocomplete>li {
  padding: 3px 20px;
}

.ui-autocomplete>li.ui-state-focus {
  background-color: #DDD;
}

.ui-helper-hidden-accessible {
  display: none;
}