Normally if you upload a new version of an attachment, any comment is wiped clear. This is the expected behavior.

However if you add a new version of an attachment by using Edit in Word (making any change and saving will add a new version of the attachment), the comment is duplicated (and unable to be changed).

Steps to reproduce:

1. Create a page and save it.
2. Go to Tools > Attachments
3. Attach a document which is able to be edited using "Edit in Word"
4. Add a comment
5. Edit the document using "Edit in Word" and save it
6. Go back to Tools > Attachments
7. Expand the attachment row to see both versions
8. See the duplicated comment (which is unable to be edited)