DateInput displays invalid date string

[dandelany]

DateInput supposedly takes either an ISO date string or a JS Date object. No matter what I give it, however, the placeholder string is completely wrong - seems like an issue with whatever is parsing/constructing strings. eg.:

const Demo = () => (
  <DateInput
    defaultValue={new Date("2018-01-08T15:44:30.000Z")}
    placeholder='DD/MM/YYYY'
  />
);
render(<Demo />);  

displays this incorrect date string:

and passing it as an ISO string:

const Demo = () => (
  <DateInput
    defaultValue={"2018-01-08T15:44:30.000Z"}
    placeholder='DD/MM/YYYY'
  />
);
render(<Demo />);  

yields a different but also incorrect result:

(in both cases, i expect 01/08/2018 to display. I'm using this demo page to test: https://grommet-nextjs.herokuapp.com/examples/grommet-controls/DateInput/_starter )