unwanted redirect to english version of a page / links are chaning unintentional

Hello Polylang-Team,

The german version of an event doesnt work:
https://exploratorium-berlin.de/veranstaltung/theater-spielen-kinder-23-2/
–> the link makes a unwanted strange redirect to the english version:
https://exploratorium-berlin.de/en/veranstaltung/theater-spielen-kinder-23-2/

With actualising the event from the Backend we could recreate the german version, but it gets an extra “-2” in the end of the link:
https://exploratorium-berlin.de/veranstaltung/theater-spielen-kinder-23-2-2/

These sudden extra-Numbers at the end of links happens in other event-pages too.
Where could this problem come from and how could we solve it?

Thank you for helping us!

• This topic was modified 1 year, 7 months ago by exploratoriumberlin.

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