Hi,

unless the website is multilanguage the URL has no redirection and it's not changed at all.

The only difference in the mobile layout must be the contents, but the URL will stay the same for the mobile too as http://www.modellbahnfreunde.ch/index.php/termine/

So this means that contents should reflect the specific menu item settings for the linked component, in your case JEvents even if the link is the same.

Things that could prevent it to work are:

1. Disabled global redirects parameter
2. Incorrect system plugins ordering (see PDF docs for correct order)
3. Third party routing extensions installed such as sh404sef