HI Mathieu,

I see that you are not fetching the value of assignment group field i.e you should use

var assignment = g_form.getValue('u_assignment_group');

now in your if loop replace compare it based on assignment and also I see that other loops you have used assignment group display value and it should be sys_id.

var assignment = g_form.getValue('u_assignment_group'); //will return sys_id

var assignment = g_form.getDisplayBox('u_assignment_group').value; //will return display value