@Greblys

did the URL http://www.example/old/old-article call a 404 error? (make sure you don't miss the TLD )

Yes, it did call 404 error

redirect plugin enabled? What exactly joomla version?

Redirect plugin is enabled. Joomla version is 3.3.6.

I'm unable to confirm a issue with this:

• install staging
• enable redirect plugin and enable collect URLs
• try to access a non existing page like: http://www.example.org/index.php/content-component_example
• 404 Error
• go to the redirect manager
• see the new entry
• edit and add a new page like: http://www.example.org/index.php/sample-sites
• save
• trx to access http://www.example.org/index.php/content-component_example will redirect you to http://www.example.org/index.php/sample-sites

please try this on a clean install of joomla 3.3.6 or staging / Nightly Builds (http://developer.joomla.org/cms-packages/) .

Coul it be that i have this issue because there is a directory called 'new' and there is menu item with alias new as well which is directing it to directory page. new-article is in new directory

You can not use a URL which contain a directory name in the path.

I will close this issue since it is a expected behavior. You are free to reopen this issue if think that your problem is not related to the given solution.