Hi,
it is unfortunately that your plugin returned the posts with /en/ for url.
It could be better that :
On En: This is working well without problem
On DE: It would be nice that the missing translation will appear and with /de/ url. This is because, I want to keep users still on language , which he or she already selected to read our post. It should not mix url German and English.
On Spanish: with urls /en/
So I think it should be working with the option wpml , when users enable WPML. Then users must not config a lot of for excluding categories.
should I install a test website with some products on different languages by using wpml ? then you can change code there ? what do you think ?