1. The tatami (folding straw mat) used in some scenes are in wrong shape. It's supposed to be square shaped, but wrongly appear as rectangle instead. Furthermore, there are scenes where people sit on the edge of a block of tatami, which actually a rude thing to do since that part is usually decorated. There's also suspicion that the arts and assets used in the game are AI generated
2. The samurai and daimyo (landlords) sitting in seiza position, in which they are kneeling on the floor. It seems innocuous, but seiza is actually became commonly practiced AFTER Edo period. Considering the game is set during the Sengoku or Warring period, it's unnatural, foolish even, to do seiza when there's always a chance that people around you are gonna kill you, since doing seiza for a long period can make your feet numb. They should be sitting on a small chair so they can react swiftly if something wrong happens.
3. There is scene where characters burn incenses at a Jinja (Shinto shrine). Shinto prayer doesn't involve any incense burning. Buddha prayer done at a Tera/Ji-in (Buddhist temple) does.
4. A scene where a person is writing kanji on a scroll is ridiculously wrong. It depicts the character writing kanji from bottom to top, whereas kanji are ALWAYS written from top to bottom, especially vertically aligned ones.
5. The family crest of Oda clan is depicted upside down on armors and such. The collectable figures also show both Oda clan and Toyotomi clan's crest which is chronologically impossible, since Toyotomi Hideyoshi just began to adopt the name "Toyotomi" from 1586, while the game is set during 1579-1584.
6. There's scene where footsoldiers bear the flag with 関ヶ原鉄砲隊 (Sekigahara Teppou-tai, lit. Sekigahara Gun Corps) written on it. Said corps is actually just established in 2012 as a movement of old flintlock gun preservation and PR of the town Sekigahara itself. This is pretty embarrassing imo, and shows how much care they put into historical and cultural research, or lack thereof.
7. The statement 私たちの侍 (watashi tachi no samurai) or "Our Samurai", during interview, where the developers said that they want to look for samurai that is "relatable" to them, i.e. non-Japanese samurai, thus they chose Yasuke. This statement took heat, because Japanese deemed it as racist. Why can't they accept Japanese, but can accept black people. Also, there's also European people in Japan back then, why not choose them? Why not other Asian?
8. Japanese are outraged because Ubisoft mentioning that the game is faithful to actual history, at least in the Japanese interview. It's even said in the interview, that we can learn about actual Japanese history through the game.
9. There's almost no trusted references mentioning Yasuke. The only historical literatures mentioning him are Shinchou Kouki (Chronicles of Nobunaga), Diary of Matsudaira Ietada, and Japan Yearly Report of Jesus Society. All of them never said that he's a samurai. At best, he's just a sword bearer to Nobunaga.
10. Twitter posts, Youtube videos, and even articles about Yasuke mainly cited Wikipedia as their source, and to surprise of no one, it's full of errors. Some examples are that Nobunaga gave Yasuke the title of lord, and the inconsitencies of Yasuke's height. It's been edited as far as from 2012.
11. In 2017, Thomas Lockley published the book "Nobunaga and Yasuke: Black Samurai who Survived the Honnoji". This is supposed to be some kind of summary of documents regarding Yasuke. In 2019, he published another book called "Yasuke: The True Story of the Legendary African Samurai" in around 400 pages. No doubt that it's a fiction novel, since even if the documents mentioning Yasuke are combined it'll be only as long as 2 pages at most.
12. Helped by the ignorance of the masses about Japanese culture and history, the edited Wiki, and maybe the "woke" culture, books by Lockley are regarded as "faithful" by many, even by some Japanese. This is indicated by many contents created regarding Yasuke in recent years, including by Japanese TV channel NHK.
13. It's only recently that after Yasuke gained more recognition that people, especially those who are in history field, began to question whether the stories about Yasuke are true or not. Some even called Lockley a fraud, since he apparently only knows about Yasuke from Wikipedia despite being an associate professor in a Japanese university.