Segment will not hand-off to Firebase in iOS app

[RBWare]

I'm in the process of migrating one of my applications from exclusively firebase, to Segment. I still want the data to make it into Firebase, but for some reason it isn't working.

I have a nearly 1:1 setup between my Android and iOS apps. Android works exactly as expected, iOS does not. If I revert to using my previous integration with firebase on my iOS app, it works fine.

This is the output error i'm seeing:
Not sending call to Firebase because it doesn't respond to track:

I'm setting up the application via segment like so:

var configuration = AnalyticsConfiguration(writeKey: key!)
        configuration.use(SEGFirebaseIntegrationFactory.instance)
         Analytics.debug(true)
        let analytics = Analytics.init(configuration: configuration)

          analytics.track("MyTestEvent", properties: event.asParamDict())

Again, when I do this, I see "MyTestEvent" come through on Segment, and all of the properties are correct. I'm just not sure why I can't get this same event to also go to Firebase.