将新的配置文件添加到现有的TestFlight构建中

So I've been using TestFlight with an app that's in development. And up until now, the Beta users haven't been changing that quickly, so it's been pretty easy to just add a new device to the provisioning file and post a new build whenever needed. But, we've recently started to quickly expand the pool of Beta users and posting a new build to TestFlight every time we want to add a new user doesn't seem like the ideal solution any longer. So I know they have the feature which lets you upload a new profile with a new device(s) in the new profile, which I'm trying to use. So at that point I then have the new user attempt to install the app and the TestFlight WebClip asks the user to install the new profile (since it's no longer embedded in the app like with the initial build/provisioning file). The user successfully installs the new profile but when going back to the TestFlight app/webclip, just repeatedly gets asked to install the profile again without being able to actually install the app.So I've been using TestFlight with an app that'