'Form outdated' error when previewing a comment on a node with an editable field

Problem/Motivation

See the error 'The form has become outdated. Press the back button, copy any unsaved work in the form, and then reload the page.' if you preview a comment on a node that has an editable field.

Steps to reproduce

From a fresh drupal 7 install, install and enable the editable fields module, then go to admin/structure/types/manage/article/display and make the Tags field editable.
Now create a new article node at node/add/article and save it, then visit the article, enter a comment, and click 'Preview' on the comment. On the comment preview page see the 'form has become outdated' error described above.
(This happens when the node the comment is being posted to is displayed in the comment preview, so wouldn't happen when previewing a comment reply to another comment for example.)