Adding some more context to this issue. My use case is i have 2 screens. 1: LoginVC 2: RegistrationVC The login screen has 2 UI textFields wrapped in a super class for embellishment. When i set the content type and secure text entry like so: emailTextField.textField.textContentType = .emailAddress emailTextField.keyboardType = .emailAddress passwordTextField.textField.textContentType = .password passwordTextField.keyboardType = .default passwordTextField.textField.isSecureTextEntry = true For a single screen this works fine. I get no debug errors and the auto fill works as expected. When i then navigate to the registration screen ( on the same navigation controller ) and set the password input to" isSecureTextEntry = true The email field ( which i didn't set the textContentType to email ) grinds to a halt. On some devices it grinds the whole phone to a halt all other apps are effected. When this email field and password field are edited i get all of the debug errors people here are seeing including this: [Assert] View <(null):0x0> does not conform to UITextInput protocol I have tried every single keyboard type combination with every single textContentType combination and still the error persists. Quite alarming if the issue can bleed out to outside of the app context too. Tested on iOS 14, 14.1 and 14.2 all the same issue on 11, 11 pro and 8.