Customers rely on the link redirections that automatically occur due to the data in the moved_issue_key table.  When they migrate, that data is no longer available on the destination site to the customer's workflows become broken. 

I was able to gather a mapping to provide to the customer using the following query:

select m.old_issue_key
     , concat(j.pkey, '-', j.issuenum) as new_issue_key
     from jiraissue j
  join moved_issue_key m on m.issue_id = j.id
 --where j.pkey = '%%'
 --where m.old_issue_key like '%%'  

Workaround:

None currently.  Will update when a workaround is available.