I've just started using ATS Pro and found a code-error in media\com_ats\js\ticket.js starting at row 36
if(this.hasClass('assignme')) { assign_to = $('#user').val(); }
Problem
.hasClass only works on a JQuery object, and this is not a JQuery object.
Solution
Rewrite rule 36 to handle this as an JQuery object, like so
if($(this).hasClass('assignme'))
Kind regards