I am using the same for cmdb_ci field on change form, but it is not working:

ref_ac_columns_search=true,ref_auto_completer=AJAXTableCompleter,ref_contributions=task_show_ci_map;show_related_records,ref_ac_columns=sys_class_name;serial_number,ref_ac_order_by=sys_class_name

Where am I missing something?

I checked on Task table field cmdb_ci and it is same what i have when cmdb_ci checked on change form.

Please assist here in.