Whenever a user changes something in an issue, Jira will notify the Exalate about the change by generating an update event. If the issue is under an update gets synchronized.
However, changing the key does not trigger such an event.
To synchronize a key change, the issue under sync needs to be touched by modifying something or by adding a comment in order to synchronize that information change. 

Additional considerations when changing the project key

  • Review the Create Processor to make sure that the old project key is not hardcoded.
  • Review the triggers and update the JQL if this is relevant