[Resolved] Transalted prodcuts do not appear in their category

Background of the issue:
I want to Make products visible on the translated version of the website.

Here you can see products: hidden link
Here, the translation of the product category, there's nothing: hidden link

As you can see I already translated the products:
hidden link
hidden link
hidden link

So why are they not appearing in their category? This was just an example, all product categories I check on the translated version are empty.

I also do not understand why the slug for the translated version is different.
Why is this: hidden link
not like this: hidden link

Why do I have to add "-en" to the category slug: hidden link
?

Symptoms:
Translated products do not appear in their category on the translated version of the website.
The slug for the translated version is different, requiring '-en' to be added to the category slug.

Questions:
Why are translated products not appearing in their category?
Why is the slug for the translated version different, requiring '-en' to be added?