I've been happy with the improved quality of language in the recent English kuroshitsuji chapters, which led me to wonder whether Yen had changed the translator since what I'll dub the "Late 2022 - Early 2023 Oopsie Woopsie Era"
so if anyone else is at all interested, I did some digging:
The same translator has been working on kuro since 2009 - however she's not a native English speaker and not entirely fluent.
A lot of manga companies used to do this, where a native Japanese speaker would do the initial translation and then other people would edit it into English that makes sense (these people are called adapters). Nowadays, most manga companies just hire native English translators who are fluent in JP. I think Yen must've skipped the adapting process on kuro for some time between 2022-23 because otherwise the sudden increase in mistakes makes no sense for someone who's been working on the series for so long (Doll's pronouns, Sebastian's literal catchphrase, phrasing that makes no sense in eng, etc). For this translator they definitely should've still kept an adapter... but it seems like they must've started adapting the translations again recently, which I really appreciate <3