I bet the cork grip on the new fly rod is a different diameter/size than your usual rod. I suspect you will find that it is smaller, forcing you into a tighter grip.
Germany is very strict. You actually have to take a class and pass a test.
https://www.angloinfo.com/how-to/germany/lifestyle/sports-leisure/fishing
"The fishing licence (Fischereischein) is obtained on completion of the Sportfisherprüfung (sport fishing exam). The fishing exam normally takes...