Confluence treats NEWS/blogpost as a page after flushing the cache. Below is the step on how to reproduce the problem:
1) login into confluence
2) open and try editing any existing blogpost
3) click preview to create a draft
4) open administration\cache statistics and flush all caches
5) in user menu go to drafts
6) resume editing from the blogpost which draft we created on the second step
7) blogpost would be opened for edit as a page; it would have page specific input fileds such as location, restrictions
8) Save the page, you will get a Page Not Found page
9) If you go to the dashboard, you will see that the news is listed as Page.