It's possible to lose data by posting a comment while editing in-place a page.
- Start editing a page in-place (edit button) and make changes in the content of the page
- Without saving, type a new comment (using WYSIWYG editor) at the bottom of the page and save it
- either the page block the post of comment informing about the possible lost of data, or the comment is posted and the in-place editing is still available with the change performed
- the comment is posted but the page is not in edition anymore and all changes are lost
Note that I didn't tested it using the text editor for comments.