Contao site; search for an extension, selection not working

The search, ''order by'' and ""compatibility"" selection for an extension on the Contao website https://contao.org/en/extension-list.html does not work. Every search or selection generates a URL with 2x the language code in the URL. Remove one laguage code from the URL and the query provides the required result.

Example: search for release 3.0 compatible extensions results in:

https://contao.org/en/en/extension-list/compat/3.0.html where it should be
https://contao.org/en/extension-list/compat/3.0.html

If after correction of the above URL you then search on an extension such as backupdb, the URL is:
https: //contao.org/en/extension-list/compat/en/extension-list/find/backupdb/compat/3.0.html

The orange part should not be there.

Same error happens on the german version of the site.

Can't reproduce this issue, sorry.

No reason to be sorry. I have placed a short recording of the issue on a testenvironment: http://holland12.com/test.html
You may have to zoom in or download the video, the text is quite small. I would like to hear if you are able to reproduce.

I have done some further testing and could reproduce the issue on 3 different pc's, all running IE9. The issue did not happen with Chrome which was installed on one of these pc's. I have also set Chrome to present itself as IE9, it still worked fine.