The country path module doesn't add a "country.url" cache context to the response. For this reason dynamic page cache stores only the page that has been accessed earlier for both countries.
Say we have country A and country B and a page /test that exists for both countries, but it's content is different. If the user accesses the page /test for country A first and then opens the same page for country B the page will look the same as for page A.
1. Configure 2 or more countries.
2. Configure domain access module.
3. Create a page that will be available for both countries but the content will be different. E.g. the view that shows a list of nodes available for the country.
4. Check this page from different countries.
Add cache country context to the response.
Needs review
1.0
Code
I have added code into the DomainServiceProvider class that alters the required_cache_contexts array and adds there a "url.county"