You are actually right. It inconsitently does not work in my case though, which was the reason why I suspected the url match I wrote was wrong.
I am not sure why and how, but it seems to have conflicts sometimes which caching / loading scripts from Divi.
I just have put a redirection javascript into the head of the respective wordpress page, to capture the cases where it does not consistently work and redirect the user after loading the head to the mobile version.
