None yet, we are looking into various possibilities. I will post back here if we find a solution

So from what we have discovered, when testflight starts the app in the background after the auto update, The app is unable to access the filesystem and thus cannot read or write any of the files. For us this was causing a crash because we are using Akavache and starting it in one of the constructors of a service. When it tries to open the database when it gets resolved, it throws an exception and crashes. Until the app is back in the foreground none of the files can be accessed at all, we haven't figured out why, perhaps the files are protected in that state. To fix we restructured the code so Akavache was lazily started, and then when the app is opened we reset Akavache's cache so that it would start working again. What a nightmare of a bug!