Usual language code mismatch issues, like T100002 and friends?

This still happens. I updated the description with detailed instructions to reproduce.

I don't understand the connection between the last step in the description and all the other steps before. Do we need to publish a translation and then view it to experience the issue?

If I only go with the last step, viewing an article on simple that doesn't have lang links, then I don't see the faulty simple english lang link that the task is about.

It probably depends on the logic in the entry point on how it chooses the languages to display and then trigger those conditions.

In T105072#10858153, @Nikerabbit wrote:

It probably depends on the logic in the entry point on how it chooses the languages to display and then trigger those conditions.

As @SBisson, I didn't see how the steps in the task description are supposed to lead to the issue, but when I tried to reach Special:CX page from any article listed on https://simple.wikipedia.org/wiki/Special:WithoutInterwiki, I am getting

Uncaught (in promise) Error: No page metadata found for title 1924 Brussels Femina Club international women's athletics meeting and language pair de-ru

Steps:
HAPPY path

• on simple wiki create a new account
• as a logged new user, go to https://simple.wikipedia.org/wiki/Special:WithoutInterwiki
• click on any article on the list, e.g. https://simple.wikipedia.org/wiki/1922%E2%80%9323_Austrian_Cup
• on the article page click on "Add language" and then on "Translate this page"
• the following page is displayed - https://simple.wikipedia.org/w/index.php?title=Special:ContentTranslation&campaign=specialcx&filter-type=automatic&filter-id=previous-edits&active-list=suggestions&from=de&to=ru#/

The lang pair is pre-set.

• a user can change the lang pair - https://simple.wikipedia.org/w/index.php?title=Special:ContentTranslation&campaign=specialcx&filter-type=automatic&filter-id=previous-edits&active-list=suggestions&from=simple&to=fr#/

The steps to reproduce the issue:

• after the previous steps, go back to Special:WithoutInterwiki and click on the same article as before - '1921–22 Austrian Cup'
• a user will be redirected to

https://simple.wikipedia.org/w/index.php?title=Special:ContentTranslation&from=simple&to=ru&campaign=ulsaddlanguages&page=1921%E2%80%9322%20Austrian%20Cup&filter-type=automatic&filter-id=previous-edits#/sx

• and on that page a user cannot change the pre-set lang pair
  • the target lang fails with

TypeError: Cannot read properties of undefined (reading 'getTitleForLanguage')

• and the source lang cannot be changed at all