await UIApplication.shared.beginBackgroundTask inside an async method

Looking for tips here. I've got Swift Concurrency Checking set to Complete - so I'm seeing interesting warnings that I'd like to hear what the proper way to fix this is.

I've got an async method that I'm using in a variety of places that I need to specify is a task that needs to complete even if the user goes into the background. It can take 2-60 seconds depending on DNS/network and server responses.

func checkRoutineDepartures() async {
        var bgTaskId: UIBackgroundTaskIdentifier = .invalid
        bgTaskId = await UIApplication.shared.beginBackgroundTask(withName: "checkRoutineDepartures") {
            UIApplication.shared.endBackgroundTask(bgTaskId)
            bgTaskId = .invalid
        }

With the complete option, I get a warning Non-sendable type '(() -> Void)?' passed in call to main actor-isolated function cannot cross actor boundary on the completion handler and then on the endBackgroundTask line I get Call to main actor-isolated instance method 'endBackgroundTask' in a synchronous nonisolated context; this is an error in Swift 6

In the docs for both of these, it says I can call them

This method can be safely called on a non-main thread.

So it seems to me like the headers are incorrectly marking the entire class as Main Actor and missing these methods, or I'm doing something wrong.