Similar in German:
https://support.mozilla.org/de/kb/pdf-dateien-in-firefox-oder-anderem-viewer-ansehen/compare?locale=de&to=312143&from=296056 incl. more formatting and even content bits reverted to EN.

Bug fix candidate for the current sprint.

@janbrasna Are there any other articles in German impacted by this? I wonder if this bug is more severe than we thought.

Haven't seen more, but definitely check with :Artist who has the gist of what all needed correcting after SumoBot — I generally mostly saw surprisingly good results, and only the additions were being touched in general, but the cases where it, perhaps for more complex formatting, went wild and touched also already-localized things, and just plowed over them, were concerning — basically MT is just translation, whereas the preexisting content was already localized by the teams, so the self-approvals overriding that human effort come across as very rude.

The only thing I'm aware of, only parallel to this issue, but a distinct problem in itself perhaps, is folks fighting with updates being constantly reverted back with regards to the actual wording in their language, e.g. in fr :YD wrestling with the same change repeatedly: 399:409 and again 446:550 — this would get exhausting soon.

That said, I do see the instructions clearly being there: https://github.com/mozilla/kitsune/blob/c17259f/kitsune/llm/l10n/prompt.py#L80-L83
so I'm wondering where and when it wants to touch things outside of the diff being tackled.

Maybe someone will have a few extra instructions how to stop messing with the excluded syntax, that also already differs being localized in the target content.