Background of the issue:
I'm trying to get the correct URLs when importing an XML feed via WPALLIMPORT. The data is inserted into a post in the primary language (ES). I want to use the SAME post for both languages. The post contains blocks of text in Spanish and English, separated by HTML. A JavaScript on the site detects if the URL refers to the primary or secondary language, loading CSS to show/hide the correct text block. I want the category URLs to be translated, but when switching from Spanish to English the URLs are correct, however when switching back from English to Spanish the URL changes. Diagram: hidden link. Link to a page where you can see the problem: hidden link
Symptoms:
I expect the URL to return to the same URL when switching from Spanish to English and back, but instead the URL changes to hidden link.
Questions:
Why does the URL change when switching back from English to Spanish?
How can I keep the same URL when switching languages?
Reference to our recent chat, I need to take a closer look at your site. So I request temporary access (WP-Admin and FTP), preferably to a test site where the problem has been replicated.
Your next answer will be private, to share this information safely.
Also provide detailed steps to reproduce the issue and links to pages in the admin and on the frontend.
IMPORTANT: Please take a complete backup of the site to avoid data loss. I may need to activate/deactivate plugins also.