I followed the article and added the recommended values to my info.plist file to disable App Transport Security and rebuilt the app, but sadly, the issue remains. Thanks for the suggestion though!

Yea, no problem! Though, thanks to the comment from the Developer Tools Engineer a few days ago, I actually realized the issue stemmed from a mismatch between the beta version of Xcode that I was using, and the beta version running on-device, so if you're able, you can update your devices to Beta 3 and then also download Beta 3 of Xcode 15, and the issue should be sorted and you can use the shorter form of declaring previews. 🙂

Sure! I’m running MacOS Sonoma Beta 3 (23A5286i) and Xcode 15 Beta 3 (15A5195k).

Sure. Here is an iCloud link that contains a screen recording of the issue that's how's that the software correctly parses the json file, but throws an "Unexpected Error" when attempting to train, as well as the exact dataset used in the recording.

I'm sorry, I actually trashed my original file since I decided to wait until Sonoma officially releases to see if my issue is hopefully resolved. I can point you to the official Apple article that I followed though. Hope it helps! https://developer.apple.com/documentation/createml/creating-a-multi-label-image-classifier?changes=latest_bet__8_8&language=objc