CKSubscription returns error that query must have at least one firing mode when using FiresOnce
<p>I have this code.  Which works when creating a subscription with a firing mode of FiresOnRecordCreation... but getting error on FiresOnce.. the error is "Query Subscriptions must have at least one type of firing mode"</p>

<p>My goal is that I have a photo.  When the first rating of the photo occurs i want to get a notification.  I do not want to use FiresOnRecordCreation on the reference as for every rating there will be a notification which is too many.  I just want the first notification for the first rating received.</p>

<pre><code>    let database = CKContainer.defaultContainer().publicCloudDatabase
    let predicate = NSPredicate(format:"owningPhoto == %@", ref)
    let subscription = CKSubscription(recordType: "PhotoRatings", predicate: predicate, options: .FiresOnce)
</code></pre>

<p>xcode crashes on the subscription but on with FiresOnce.</p>