In my organisation JIRA was introduced before Aha. When synchronizing between JIRA and Aha there will come a Unique Issue ID for Aha and the original Issue ID from JIRA will also be used for that Issue. Now you have two references for the same issue. This is not a good idea for the process in the Company when communication about releases to other colleagues. THe reference from JIRA should ofcourse be synchronized together with the issue so the JIRA issue is kept.