Set null initial state to prevent null dates.

src/components/Utils/ControlledDateTimePicker.tsx

@@ -19,6 +19,7 @@ export const ControlledDateTimePicker: FC<DateTimePickerPropsType> = ({
   <Controller
     control={control}
     name={name}
+    defaultValue={null}
     as={({ ref, ...rest }) => (
       <KeyboardDateTimePicker
         margin="normal"