RESOLUTION [Approx 10:40am CT]:
Our developers have pushed a fix for the Xcode 9 build issue and we have confirmed the issue should be resolved.
Please let us know if you continue to have any problems, and thank you for your patience.
CONFIRMING FIX [Approx 10:30am CT]:
The issue has been identified and we're currently confirming the problem has been resolved.
We hope to have a full resolution shortly.
INITIAL REPORT [Approx. 8:00am CT]:
Our developers are currently investigating an issue with Xcode 9 Package builds in Ionic Pro.
In the meantime, we recommend using Xcode 10 or Xcode 8 for building your iOS applications as those appear to be unaffected by the problem.