PropType.shape({}) Failure Warning: Invalid Type

I'm trying to set up the PropType of a prop from a Redux-State which is an object that looks like this:

sDate = {
        all_day: true,                               //bool
        category: "sCategory",                       //string
        created_at: "2021-07-31T10:06:02.545637Z",   //string
        description: "sDescribtion",                 //string
        end: Sat Jul 31 2021 14:05:00 GMT+0200       //Date
        id: 49,                                      //number
        start: Sat Jul 31 2021 16:05:00 GMT+0200     //Date
        title: "sTitle",                             //string
        type: "sType",                               //string
}

At least, this is what it looks like inside the axios.get request function right before dispatch. I can also read out the content of the object inside the Component. I'm using it in a function Component, as you will see below.

First, I tried to set it up as PropType.object.isRequired, but I got the warning

Warning: Failed prop type: Invalid prop `sDate` of type `array` supplied to `EditDate`, expected `object`.

Changeing to PropType.array.isRequired results in the warning

Warning: Failed prop type: Invalid prop `sDate` of type `object` supplied to `EditDate`, expected `array`.

That's when I decided to use PropTypes.shape({}).

Below, you can see the function component with the current PropTypes setup

function EditDate(props) {

    useEffect(() => {
        props.getSingleDate(id)
    },[])

    const { id } = useParams();

    return (
        <Fragment>
         ...
        </Fragment>
    );
}

EditDate.propTypes = {
    getSingleDate: PropTypes.func.isRequired,
    deleteDate: PropTypes.func.isRequired,
    sDate: PropTypes.shape({
        all_day: PropTypes.bool.isRequired,
        category: PropTypes.string.isRequired,
        created_at: PropTypes.string,
        description: PropTypes.string.isRequired,
        end: PropTypes.instanceOf(Date).isRequired,
        id: PropTypes.number.isRequired,
        start: PropTypes.instanceOf(Date).isRequired,
        title: PropTypes.string.isRequired,
        type: PropTypes.string.isRequired,
    }),
};

const mapStateToProps = state => ({
    sDate: state.dateReducer.dates
});

export default connect(
    mapStateToProps,
    { getSingleDate, deleteDate }
)(EditDate);

I still get the warning

Warning: Failed prop type: Invalid prop `sDate` of type `array` supplied to `EditDate`, expected `object`.

What am I doing wrong?

I also tried changing the Redux-Reducer, because it might be set up the wrong way:

const initialState = {
    dates: []               //  <-- does this determin what React expects?
};

export default function(state = initialState, action) {
    switch (action.type) {
        case GET_DATES:
            return {
                ...state,
                dates: action.payload
            };
        case GET_SINGLE_DATE:
            state.dates = Object    //  <-- this had no effect in the matter discussed
            return {
                state,
                dates: action.payload
            };
            ...

In the above example, in case GET_DATES I don't get any problem with the action.payload as props in the corresponding Component (there, PropTypes.array works).

EDIT:

this works:

sDate: PropTypes.oneOfType([PropTypes.array, PropTypes.object]).isRequired,

Can someone explain to me why? The docs are a little bit vague on it.

EDIT 2:

I had to correct a logical error in the Redux Reducer: GET_DATES and GET_SINGLE_DATE really shoud have their own representation in Redux-state:

const initialState = {
    dates: [],                
    sDate: []                
};
...
...
        case GET_SINGLE_DATE:
            return {
                state,
                sDate: action.payload
            };
            ...

EDIT 3:

As explained in the answer below, I had to change the initialSate of the Reducer, i.o. to make it work right:

const initialState = {
    dates: [],                
    sDate: {}      //now, the initial state is an object, too                
};

therefore, to make proper use of it:

EditDate.propTypes = {
...
  sDate: PropType.object.isRequired,
...
}