One of the possible ways to show original issue key on the twin issue is to copy that key into the text custom field. 

This article shows how to copy the original issue key to a custom field in the twin issue.

Steps to copy the original issue key in a custom field:

 All steps should be performed only on the side, where you want to show the issue key from the other instance.

  1. Create text custom field on the Destination Jira instance(the side where you want to show the original issue key).
  2. Add the code below into the Outgoing sync(data filter) on the Source side 
    Source side 
    Outgoing sync (data filter)

    replica.key = issue.key

  3. Add the code below into the Incoming sync (create processor) on the Destination side to copy original issue key to the previously created custom field.

    Destination side
    Incoming sync (create/change processor):

    issue.customFields."Text Custom Field Name".value = replica.key

    note

    "Text Custom Field Name" is the name of the custom field, you've created in the first step.

  4. Save changes.
  5. Exalate the issue to see how it works.

    Here is an example how it looks once you synchronize the issue.

       

 

See also