Release information in appdata / metainfo is not translated
There is provision in Appstream to translate release notes, even after a release has been made (via external urls)
AppStream catalog metadata generators may choose to update the locally provided release information with the data from the web location provided by the URL in url. This allow projects to complete release localization after a release was made, or include further information that was not yet available directly at release time. The generated catalog XML data must be complete and must not contain references to external release information.
Source: https://freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-releases