Markdown not parsed

I can’t get markdown parsing working in calendar descriptions:

– JP Markdown plugin is installed and activated
– The calender list is displayed as widget
– The feed is configured with [description markdown="true"]
– The events description looks like

Siehe [Beitrag](http://neu.dtv-wettingen.ch/wordpress/2015/03/14/kreis-minitramp-meisterschaft)

– The very same text is printed in my calendar widget

Do I miss something? Help is very appreciated!

https://wordpress.org/plugins/google-calendar-events/