device.platform returns null on iOS

I'm in the process of testing a cordova app on iOS using Testflight, but I'm having an issue with the device plugin. While it works fine in the XCode simulators as well as on a physical device when installed via XCode, the versions downloaded from Testflight all return device.platform = null. On Android it also works fine.

I've worked around it by testing for device.platform !== "Android" instead of doing device.platform === "iOS", but I would prefer to have the plugin work as expected. Any ideas what's going on here?

cordova-plugin-device 1.0.1 "Device"
Installed platforms: android 4.1.1, ios 3.9.2