application:openURL:options: not called after opening universal link

I've set up universal links with the Branch SDK. The links are opening the app correctly, and application:continueUserActivity:restorationHandler: is called, but not `application:openURL:options:'

func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
    Branch.getInstance().application(app, open: url, options: options)
    return true
}

The deprecated application:openURL:sourceApplications:annotation is also not called. didFinishLaunchingWithOptions and willFinishLaunchingWithOptions both return true.

What could possibly causing openURL to not be called when the app opens from tapping a universal link?