A semi-common occurrence is an app startup failure due to permissions dialogs starting before Calabash has begun. This is a known limitation, and is documented here: https://github.com/calabash/calabash-ios/wiki/Managing-Privacy-Alerts%3A--Location-Services%2C-APNS%2C-Contacts.
However, Test Cloud users who hit this behavior don't see any clues that they could use to diagnose this and fix it; because no screenshot is shown to them of the permission error and even if it were they might not be aware of the cause of the issue.
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