I'm experiencing this too, even with the updated Beta 2. About the only workaround I was able to find was to install the .ipa using Apple Configurator. However, I seem to be running into an issue where it reads different apps as the same app saying name of app/ipa is already installed on this device, do you want to skip/replace/stop, even though it is not. So, if you have one specific app that you want to install, this will work. However, installing multiple apps may not. Hopefully, installing via Xcode will be fixed soon.