Redirecting to homepages instead of language versions

Hi there,

I the language switcher on the menu I use on all english pages. Only on this page: https://dantasy.breynaert.eu/en/category/en/projects/, clicking the other languages redirects to the homepage instad of their versions. Also, in the admin, these are linked page versions and are not standalone.

I don’t use caching plugins.
Which is strange, in the other languages, the projects page redirects to the homepage of that language in some cases.
– Dutch: https://dantasy.breynaert.eu/nl/category/nl/projecten/ redirects french and US to their homepages
– French: https://dantasy.breynaert.eu/fr/category/fr/projets/ redirects US to its homepage.
– Only on the US page, everything works as it should https://dantasy.breynaert.eu/en-us/category/en-us/projects-overview/.

Any ideas?

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