Demo...
Chosen date was 2020/09/06...
... times are output in UTC, I am in UTC+1 (so add the offset and you get 00:00 of the correct date)
The issue is purely visual - the date / time is in-fact correct, merely represented as UTC.
If need be, you can use a function like below to get a local date/time representation...
function convertUTCDateToLocalDate(date) {
var newDate = new Date(date.getTime()+date.getTimezoneOffset()*60*1000);
var offset = date.getTimezoneOffset() / 60;
var hours = date.getHours();
newDate.setHours(hours - offset);
return newDate;
}