Links in rss comes with .rss ending in production mode, why?

Hey

I’m facing the problem, that in development mode, the generation of
the links in the RSS Feed is correct, but when they will be rendered
in production mode (passenger 2.2.x)
I recieve all link with the ending .rss

feed://www.mbt-ag.ch/vacancies.rss?rss_type=native&debug=1

May you can help me? I really have no idea, what the problem could be

Thank you very much!

Rafael