Eh, let me play Devil's Advocate here for a second. English is a very sexed-language. When the Normans took over England and mixed French, Latin, and Greek into a mostly Germanic language we lost most of our non-sex specific pronouns which in the long run led to a lack of them in the modern day. The fact that we don't have as many as Japanese is why when translating from Japanese to English for a person of uncertain gender we often have phrases such as "That Person", "Them" "That Child" or "That Guy" in places where it sounds clunky and unnatural in English but would sound totally fine in Japanese.
When writing or translating, a large amount of the time you are working off of the best constructed versions of the translation and what sounds the most natural in a given language is often the version that makes it through which can allow for small mistakes like this to get passed through even if not technically the intention of the author. These are just a small amount of problems that are easy to trip up on in translation. I understand that you might expect more for a product you paid for, but the translation quality isn't always going to be consistent (especially because more often than not more than one translator works on it) and language foibles aren't going away soon which can make the job harder.
I typed all this when I could have said it all in a much smaller post. Being VP is suffering.
They, them, theirs. All proper, all used for centuries for a singular unspecified person. I do agree that translating is difficult and some things are bound to slip through the cracks, regardless it makes for a jarring experience for some.