In Ann Leckie’s Imperial Radch stories, all Radchaai are styled using the she/her/hers pronouns, by custom, but also from the point of view of an AI that plain doesn’t understand gender.
In this series, we learn that the “she/her/hers” pronouns used are definitely the feminine ones. When the narrative turns to a non-Radchaai culture with separate genders, a sibling of a person is referred to as her brother, a concept that had no words in Radchaai, which meant that the speaker had to switch to a different language, Delsig, to correctly convey the sentiment.
In her book Provenance, in the same setting, Leckie presents a Radchaai citizen from the point of view of a person from a gendered culture; the point-of-view character is confused by the Radchaai’s apparently mismatched gender cues. The Radchaai, raised in Radchaai culture and speaking Radchaai, stubles when using pronouns for non-Radchaai people and often slips by referring to them using pronouns that are, to the point-of-view character’s ear, feminine.
In Ann Leckie’s Provenance, Hwaean nemen (a third gender of human) are styled using e/eir/eirs pronouns, by custom, but also from the point of view of a high-class Hwaean woman.
These pronouns are kept when the Hwaean language Bantia and the outsystem language Yiir are translated into English by the author.
TvTropes’ article on Provenance has this to say about the Hwaean approach to gender:
The Hwae recognize at least three genders mentioned in the book: “Man”, “Woman”, and “Neman”, with the latter having its own set of pronouns. The book does not give any details on the meaning, cultural significance, sexual identity or gender/biological roles associated with nemen, though to be fair it doesn’t do that for “he” or “she” either. Additionally, children are referred to with the singular “they” and choose a gender and a name in order to become adults. Usually they do this in their late teens. Taucris delayed until her midtwenties, when she realized she had to be an adult to hold her dream job, and wasn’t totally happy with having a gender after choosing.
In Ada Palmer’s Terra Ignota, by custom all humans are styled using the neuter pronouns “they/their/theirs”, but the in-universe author of most of the first three books uses gendered pronouns as suit his understanding of Eighteenth-Century gender roles.
In some situations, the author is ordered to use particular pronouns for one character, in light of their genitals, but later switches to using the stereotypically opposite set of gendered pronouns in light of the character’s demeanor, bearing, affect, and role in the history that the author writes.
In other situations, you get oddly mixed references, such as this English translation of French, spoken to someone who was raised in gender: “Your noble sister is safe. I spoke to them today.”
Cryptovexillologist notes that the in-universe author’s approach to pronouns can be described as “backwards gender essentialism”: not “you’re a man, therefore you do these things” but “you do these things, therefore you’re a man”.
That same author tries very, very hard to avoid using pronouns for one group of humans, who though they assuredly reproduce, don’t really have gender roles. This batch is the Utopians, who “vow lifelong … I will commit the full produce of my labors to our collective effort to redirect the path of human life away from death and toward the stars.” They care not for petty human things; instead considering the benefit of the species.