Hello Rob,
The live site currently uses no subdomain and is in the "method" address. The stage site uses the new app subdomain and is in the "stage" address. The proper one is the first one for the July version. To me, it seems you have stumbled on the 'placeholder' where the July live version will go once live (which is the second one). It is currently not available. That's also why you can't switch between versions.
If you create a portal in July stage site to take advantage of new developments, your customers will have to log into https://app.methodintegration.com/stage to also use the new developments. For live site portals, you can use https://www.methodintegration.com/method.
I apologize for the inconvenience the new subdomain has caused. I know bookmarks and imbedded links on websites will have to be changed with the new subdomain. I haven't confirmed the change but it does seem when July goes live, it will also be under the app subdomain.
Greg