As discussed in https://engineering.redhat.com/rt3/Ticket/Display.html?id=81926 the import script should set the last_closed custom field. The most recent import I have done shows that this value was not set.
SELECT bug_id, cf_last_closed FROM bugs WHERE bug_status = 'CLOSED' AND bug_id IN (SELECT bug_id FROM bugs_aliases WHERE alias LIKE 'JBPAPP-%');
Will need to modify the import script to populate this field as required.
This change has been made, and will be done on the next import. Since this custom field is mainly used for reporting, there isn't a need to do a new import just to test this.
For those wanting to test it before the next import https://import.bz-devel.eng.bne.redhat.com/ for the SOA product bugs have this field set.
I'm marking is as ON_QA. I will do the testing on the next import to check that this works as expected. No need for the JBoss testers to do anything.