TYPO3 Core

Seems to be the same problem as the one I just stumbled across.

I'm using "German AT"(default) and "German DE"(second language)

In Connected Mode I can translate everything and the translation is correctly shown for DE.
Using Copy-mode leads to an untranslated page. If I create content in DE only, it is never shown.

Heres the siteconfig:

base: 'https://domain.at/'
baseVariants: {  }
errorHandling: {  }
languages:
  -
    title: 'Deutsch AT'
    enabled: true
    base: 'https://domain.at/'
    typo3Language: default
    locale: da_AT.UTF8
    iso-639-1: de
    navigationTitle: 'Deutsch AT'
    hreflang: de-AT
    direction: ''
    flag: at
    languageId: '0'
  -
    title: 'Deutsch DE'
    enabled: true
    base: 'https://domain.de/'
    typo3Language: de
    locale: de_DE.UTF8
    iso-639-1: de
    navigationTitle: 'Deutsch DE'
    hreflang: de-DE
    direction: ''
    fallbackType: fallback
    fallbacks: '0'
    flag: de
    languageId: '1'
rootPageId: 1
routes: {  }

Maybe someone knows a temporary solution until this is solved?

Same here. The fallbacks directive is ignored and the default language is always shown.

Same problem as Lars. We tried basically the same they did. Create 4 "base languages" and use the language variants with fallbacks to one of those 4 base languages. The settings in sites.config are simply ignored.

Example:

1. Base language EN
2. Second language DE (strict, no fallback language defined)
3. Third language DE-AT (fallback, DE is fallback language)

Result:
EN is shown. If we switch to strict in DE-AT the page is empty. We've tried all possible combination of using the defined sites.config fallback languages, with strict, free, fallback mode, different languages etc. they are always ignored. If fallback is activated it always goes to the base language as fallback source, just like it did in TYPO3 < 9. This also applies to version 10. Is there any way this feature introduced years ago in 9 does anything noticeable? Or what is the supposed function of defining fallback languages if they are not used for... fallback?