During cloud-to-cloud migrations with the Copy Product Data feature, the hierarchical (nested) structure of comments is not preserved. All comments, including those that were replies to other comments (nested), are migrated as top-level (flat) comments on the destination site. This results in the loss of comment threading, making it difficult to follow the original conversation context.

Steps to Reproduce:

1. On the source Atlassian Cloud site, create a Jira issue with nested (threaded) comments.
2. Use the Copy Product Data tool to migrate the project to another Atlassian Cloud site.
3. Review the comments on the migrated issue in the destination site.

Expected Result:

• Nested comments retain their parent-child relationships and appear as threaded replies after migration.

Actual Result:

• All comments appear as flat, top-level comments.
• The original nesting/threading is lost.

Impact:

• Loss of conversation context and readability.
• Potential confusion for users relying on threaded discussions.
• Manual effort required to reconstruct comment threads post-migration.

Notes:
This is a current limitation of the Copy Product Data tool. At this time, there is no workaround to preserve comment nesting during migration.