Warning not triggered when using the browser back button if only one field has been modified and that field is not using wysiwyg

I have found that when adding a new node or editing an existing node, if you make a change to only 1 field that does not use a wysiwyg (plain text textarea, text field, or radio field), click nowhere else on the page (field is still active) and click the browser's back button, the message does not get triggered. This is only when using the back button, and not when clicking a link, and only if the first changed field is still active.

Replicate:
* add or edit
* add some text to the title, or change a radio value (such as workflow state)
* without first clicking anywhere else on the page, hit the browser's back button, you will be taken back without a warning

I have tested in both Chrome and Firefox with the same result