If you are not using custom locale files (manually put some some files in your custom directory), then maybe it’s a code/build/packaging bug of the FreeBSD release?
The full story is: when Gitea starts , it registers some internal tasks, these tasks need locale translation, so Gitea tries to translate the task names by its builtin/custom locale files. If Gitea can not find the related translation string, it reports fatal error, because in such case the locale system doesn’t work.
The 1.19 locale file is : gitea/locale_en-US.ini at release/v1.19 · go-gitea/gitea · GitHub
You can check Gitea’s builtin assets by ./gitea embedded {list|view} command, to see whether your binary has the builtin assets.