Language Problem

Hello again,

I have a problem with my project with different languages.

Sometimes, just sometimes the web redirects wrong and I get an error.

Instead of the language code, the web writes themes, here the example

it should be

www.myweb.com/en/site/

but i get

www.myweb.com/themes/site/

If I am logged in I got error message, as well I go to that web using redirect

But if I am not logged in, the route is with themes but I can navigate.

This it happens and I do not know why, I have URLManager setup with the language and I set in the session the value of the language too.

any help?