Manage Languages does not have 3-tier language available for locales ending on _SF. As example below:
SAP SuccessFactors HCM Suite
The instance was not locale migrated to the new locales.
New locales follow 5 characters name convention, where the first 2 are the language, then a '_' and 2 characters to the country. Below you can see some examples:
en_US, de_DE, fr_FR, fr_CA, etc.
When enabling language packs, if there is any locale IDs ending with _SF the instance should be locale migrated (Language Migration).
Manage Language option shouldn’t be enabled for instances where _SF suffix is visible in Provisioning -> Company Settings.
Enabling may cause some fields in the system not translate properly (PLT-30434). You should also not change the language pack from the language with _SF suffix to a language without _SF.
For example, if the de_DE_SF is already checked, do not switch to de_DE, instead, you need to raise an incident with support on component LOD-SF-PLT-LAN and ask for a language migration.
KBA , sf internal , sf v12 , sf language , sf t3 architecture , LOD-SF-PLT-LAN , Manage Language & Text Replacements , How To