How to migrate newly created comments in the source instance when the snapshot is already deployed in the target instance
When creating and deploying a snapshot, there can be cases where users in the source instance add new data to the issue, such as comments, changing the status, modifying the assignee and other fields, etc. We might also need this additional information added to the target instance in these cases.
Configuration Manager for Jira doesn’t change existing issues. The CMJ app only supports two use cases:
Deploying a new project and all of its issues.
Importing new issues into an existing project.
If the project exists on the target instance, CMJ will deploy only the issues whose keys don’t exist on the target instance; the existing issues will remain unchanged.
 Workaround for adding new data to already deployed issues
In the target instance, locate the issues that need to be updated with new comments or any other changes.
Go to the source instance and create a new snapshot with the new information.
In the target instance, delete the already existing issues (located in step 1) that must be updated with the new changes.
Deploy the snapshot in the target instance to visualize these new changes on the selected issues.
Now you should be able to view the new comments on the issues.