I'm using Crashlytics Beta to send new builds of my app to my tester.
However, when distributing a new build, the current users don't get the popup telling them that a new version is available. Their status on the dashboard stays at "Installed" and never get to "Launched", maybe it's linked?
I also regularly get "logged out" of the Beta webclip on the home screen, with a "Well, this is odd" error message.
Beta polls for new updates on iOS every 2 hours. If you're doing multiple releases in a 2 hour period the pop-up won't appear for each release.