I have created an app on swift and tested it extensively using iPhone 6, iPhone 6 plus and iPhone 5 devices and all the simulators offered in Xcode. The app runs fine and does not crash when uploaded locally. (iOS 8)
I finally submitted a build for Testflight. The app consistently crashes at the same place after downloading the app through the Testflight build.
Is there a known issue where uploaded builds run differently than locally created builds? And how can I debug the issue with the Testflight build?
I solved the issue by changing the swift compiler optimization from fastest to none. I'm not sure if this is an ideal long term solution, but the build no longer crashes.