Anonymous Sharing not working with Communication sites

Have you added everyone in your tenant to "First Release - Select User"??

I have been playing around with Comms sites, but everyone who I send a link to who isn't in "First Release - Select User" get very strange rendering and pages aren't usable, so I guess the First Release group isn't just to get access to "create a site" it's to actually get access to web resources also.... Can anyone confirm this??