PrimeNG <p-calendar> "Invalid time" and "value.getDate is not a function" errors

We use PrimeNG v6.x in our Angular project and use some calendar with time on some forms. However, although we have the following configuration and return Json from controller in dd.mm.yyyy HH:MM:ss format, we encounter “Invalid time” and “value.getDate is not a function” errors. I think there must be a format conversion problem, but have not fix the problem yet by looking the issues on the web.

Model:

[DisplayFormat(DataFormatString = "{0:dd.MM.yyyy HH:mm:ss}", ApplyFormatInEditMode = true)]
public DateTime FinalDate { get; set; }

In the *.ts file we make the following configurations:

...
showTime: true,
hourFormat: '24'

The dates are returned in “dd.MM.yyyy HH:mm:ss” format from the controller. But even this, get the same errors. Any idea?

Source: AngularJS