When the app language is set to Chinese or Korean in Settings > Language, date separators in the chat history (e.g. "October 27") still display English month names.
Dates provided by the language pack, such as FormattedDate.ShortDate.m10, are translated correctly for Korean. The macOS system language and region are also set to Chinese, so the system locale does not appear to be used for these separators.
The issue appears to be related to the app bundle's built-in localization, which contains only en, de, es, it, nl, pt-BR, ru, and uk. Other languages therefore fall back to English.
Verification: With Telegram's language still set to Chinese or Korean, changing only the app's macOS language to German using defaults write ru.keepcoder.Telegram AppleLanguages -array de and relaunching the app causes the date separators to display German month names.
Steps to reproduce
Go to Settings > Language and select Korean or Chinese.
Open any chat containing messages from several different days.
Observe the date separators between messages.
Current result
Date separators display English month names, regardless of whether the selected Telegram language is Chinese or Korean.
Expected result
Date separators use the selected Telegram language, displaying localized dates such as 10월 27일 in Korean or 10月27日 in Chinese.
Device info
Telegram macOS 13.1.0 (283357) STABLE, MacBook Pro M5 Max, 26.6.2