Background of the issue:
We have a multisite setup per country, with each country having its own set of languages. We are using a setting where even the default language appears in the site URL. For example, the URL for the USA site looks like: скрытая ссылка for English and скрытая ссылка for Spanish. When I open the sitemap by URL скрытая ссылка, I see that the post and pages sitemaps are leading to a 404 page. The URLs there do not contain the language code. When I manually change the sitemap URLs in the browser to contain the language code, it works well. Here is the link to a page where the issue can be seen: скрытая ссылка
Symptoms:
The post and pages sitemaps are leading to a 404 page because the URLs do not contain the language code. Instead of скрытая ссылка, the URL is скрытая ссылка, which leads to a 404 page.
Questions:
Why are the sitemap URLs not including the language code?
How can I ensure that the sitemap URLs include the language code?