[Geschlossen] Translation slug returns 404

Background of the issue:
I have a page at versteckter Link with 3 translations. The issue is with the Traditional Chinese (zh-Hant) version. The page slug for this translation should remain in English, like this: versteckter Link. I'm manually changing the slug on the CH (Tr) edit page here versteckter Link.

Symptoms:
When I change the slug to the English version ('academy'), the page immediately starts returning 404.

Questions:
Why does the English slug cause a 404 on the zh-Hant translation?
How can I fix the issue with the English slug causing a 404?