Swift - 使用两个不同的OperationQueue和KVO时应用程序崩溃

I'm getting two type of information with JSON and I'm adding "operations" to 2 different Operation Queues Classes with addObserver(forKeyPath:"operations"...). In the function observeValue I'm checking if operationQueue1.operations.isEmpty and then I refresh my information in UI. I'm doing the same thing with if else with operationQueue2, but when the 2 operations are started in sometime the application crash with error message: I'm getting two type of information with JSON a