Deleting an attachment version causes all labels to be removed from the page

Issue Summary

When you delete a version of an attachment attached to a page, any labels added to the page will be automatically removed.

 This only happens when an attachment has multiple versions and you remove one of them, leaving at least one version of the attachment still attached to the page.

If you remove an attachment with only 1 version, the bug doesn't occur.

Steps to Reproduce

1. Create a new page.
2. Add an attachment to the page.
3. Add labels to the page and save it.
4. Navigate to ... > Attachments and add a 2nd version of the same attachment.
5. Remove any 1 of the 2 attachment versions.
6. Go back to the page.

Expected Results

The labels should still be intact on the page.

Actual Results

All labels for that page are missing.

Workaround

Currently there is no known workaround for this behaviour. A workaround will be added here when available.

We suggest sticking with our latest Long Term Support (LTS) Release - Confluence 7.4.4, which is not affected by this bug.