superagent adding invalid characters on a post request on IE11

Hello,

Following is my code
id = 1234556
startDate=2-2-2018
endDate=2-11-2018

export function getDataByDate(id, startDate, endDate) {
return (dispatch) => {
const url = '/api/getDataByDate/v1';
request.post(url)
.type('application/json')
.send({ id,
startDate,
endDate }).use(nocache)
.end((err, res) => {
if (err) throw err;
dispatch(receivedData(res.body));
});
};
}

When I see the network traffic it shows as
{"id":"43491486","startDate":"?2?-?6?-?2018","endDate":"?2?-?12?-?2018"}

Why superagent is adding these special characters to the request on IE11. This code works fine on chrome. Is there any special thing I need to add to request for string's having special character in request for IE11.