On iOS 16.6+ systems, after the prompt to save the password to iCloud Keychain pops up, if you immediately background the app and then return to the foreground, all input fields cannot bring up the keyboard.
There is a bug in iOS 16.6+ systems where UITextField is unresponsive.
All input fields are unable to bring up the keyboard.
I am confident that this is a bug from Apple. When will this issue be fixed?
You should file a bug report using the link below and reply back with the bug number.