Textfield works very weird in iOS 17, how to fix?

I have the following code working great in iOS16

TextField(
            "Describe...",
            text: Binding(
                get: { promptText },
                set:
                    { (newValue, _) in
                        if let _ = newValue.lastIndex(of: "\n") {
                            isFocused = false
                        } else {
                            promptText = newValue
                        }
                    }
              ),
            axis: .vertical
        )

but in iOS 17 it breaks. But it breaks in a very mysterious way.

Firstly, the @ FocusState doesn't work.

Setting it to false does not dismiss keyboard. Fine, but also what's weird is that when I press the done button, the new line gets added to the textField anyway, even if I don't set the newValue. What's going on?