NSFetchedResultsController predicate updating

When using a NSFetchedResultsController with a predicate that excludes items, the items won't be included in the NSFetchedResultsController even if they are updated to no longer be excluded.

An example from our app: We use a NSFetchedResultsController to power the users' contacts table view but don't want to display users who we don't have a subscription to. So our predicate says subscription != "none", which excludes those users from the NSFetchedResultsController. The problem happens when one of those users accepts a request, at which point they should be shown on the list but since they were previously excluded from the fetch request, they won't be added.