last post in specific category links to previous post in different category

Hi
n my travel website I have “Berlijn 2018” set as a static home page. This is my opening page for my daily the posts about this cycling trip. On this page i want to display all the posts with the category “Spreewald 2018″.
For this I use the shortcode:
[catlist name=”Berlin 2018″ order=desc numberposts=-1 excerpt=yes ?excerpt_size=30]
This works as exepected.
However: at the bottom where ‘next/previous” is shown, when clicking “previous” as post is displayed “Weer thuis” which belongs to a completely different category “Bremen 2017”.
How can I set the link back to the main page when the last post in a specicific category is reached?

The page I need help with: [log in to see the link]