[Закрытые] Spanish blog page redirects to the homepage

Background of the issue:
I have fully translated a blog post into Spanish. When I visit the English version of this post and use the language switcher to switch to the Spanish version, I am redirected to the homepage instead of the Spanish translation. The issue can be seen at: скрытая ссылка

here is the screen recording: скрытая ссылка

Symptoms:
Clicking the Spanish language switcher on the English blog post page redirects me to the homepage instead of the Spanish translation of the post.

Questions:
Why does the language switcher redirect to the homepage instead of the Spanish post?
How can I fix the language switcher to correctly link to the Spanish translation?