UIDocumentPickerViewController allows selecting a file the first time the app is run, but not subsequently - swift

Question

My app, when run, creates a json document (using a UIDocument subclass) in its document directory. And then, when opening up the UIDocumentPickerViewController to select a file, if the app has written a new file, the behaviour is as expected.
However, if I run the app again (and overwrite the last created file), the delegate method didPickDocumentsAt doesn't get called, unless I browse around for a few seconds.
What am I missing here?
#IBAction func showDocumentPicker() {
let documentPicker = UIDocumentPickerViewController(documentTypes: [kUTTypeJSON as String], in: .import)
documentPicker.allowsMultipleSelection = false
documentPicker.delegate = self
self.present(documentPicker, animated: true, completion: nil)
} //this function is in the initial definition of the class and is connected to a UIBarButton
extension BudgetExportViewController: UIDocumentPickerDelegate {
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
print("selected document: \(urls.first)")
print("555555555555555555555555555555")
//document = BudgetExportDocument(fileURL: urls.first!)
// CFURLStartAccessingSecurityScopedResource(urls.first! as CFURL)
// let documentData = try? Data.init(contentsOf: urls.first!)
// let json = try? JSONDecoder().decode(BudgetExportData.self, from: documentData!)
// budgetThisMonth = json
// print("Budgetthismonth")
// print(budgetThisMonth)
// CFURLStopAccessingSecurityScopedResource(urls.first! as CFURL)
}
}

Answer 1

Apparently, the problem was the fact that I was overwriting the same file so many times. Now, if a file with the same name exists, it won't write over it and the UIDocumentPickerViewController behaviour is as expected.