[Fechado] Multi-domain setup causes issue with product-category and product urls

Background of the issue:
I initially installed WPML and translated the site to German on a dev-server, where the languages were configured to 'Different languages in directories'. The German language loaded in /de and everything worked fine. We moved the site to the production server and everything still worked fine. We then set up a separate domain for the German and other languages. I configured the domain to domain-name.de and the site works - except for WooCommerce product-categories and product pages.

Symptoms:
Products fail with a 'domain-name redirected you too many times.' error and product categories trigger a 404 page and a strange URL. The product category structure on the base English language is /product-category/vests/. The German structure should be: /produkt-kategorie/westen/ but clicking a link to a category produces this link /product-category/e/westen/. If I go to String translation and delete the URL slug for product in the WordPress domain, I can now click a product but it uses the URL structure of the base English language /product.

Questions:
Why are product categories not translating correctly and showing a strange URL with an /e added?
How can I resolve the 'domain-name redirected you too many times.' error for products?
Why does deleting the URL slug for product in String translation affect the URL structure?