To be able to see the problem, the setting site.ini -> regionalsettings -> showuntranslatedobjects must not be enabled, and all objects must have the checkbox (located in the tab translations of the object) "Use the main language if there is no prioritized translation" disabled.

generically, the problem can be described as: if an object A in a tree does not have a translation X, navigating with the siteaccess sit_X that uses that translation to the object A causes the child objects to show with system urls instead of nice urls. same for parent objects.

Steps to reproduce

Foo and Bar can be custom or default languages:

1. install 2 additional languages, Foo and Bar.

2. create the siteaccesses Foo and Bar. each siteaccess has it's own language plus eng-GB in second place in the SiteLanguageList[] setting

3. Set the home node with eng-GB, Foo and Bar translations

4. create a structure of folders with different names for each translation, to best keep track of the objects called:

Home node : translations for eng,foo,bar

5. in frontend, enter siteaccess foo, and the folder "folder in bar - uk trans" shows up. click on the folder, and the subfolder "folder in foo" shows up. notice that the url for this folder is a system url. click the "folder in foo". the article shows up as "article in bar- foo trans", with a system url.