One of attribute lost data when assign javascript object

I spend a day for investigating this case, but seen no hope.

const Tests = (state = INIT_STATE, action) => {
switch (action.type) {
case GET_TEST_DETAIL:
return {
…state,
test: {},
error: {},
updatingTest: true,
}

    case GET_TEST_DETAIL_SUCCESS:
        const test = action.payload
        console.log(action.payload.shortName)//has data
        test["shortName2"] = action.payload.shortName//has data
        test["shortName"] = action.payload.shortName//empty string

        console.log(test)

        return {
            ...state,
            test: test,
            updatingTest: false,
        }

There is the picture captured when I console.log in firefox, and Edge:
enter image description here