when I bring the cursor over datetime input text the existing date value will be disappeard from the input text

Hi

After setting the value of Expiry date and PenaltyExpDt to the corresponding input text, and after when I place the cursor over  there, the value would be disappeared from the textbox. Why that date is no longer stay when I put the cursor over the textbox of  datetime

LicenseModel
public int DocCatID { get; set; }
public DateTime? ExpiryDate { get; set; }
public DateTime? PenaltyExpDt { get; set; }
NotMapped]
public string PenaltyExpDttxt { get; set; }
[NotMapped]
public string ExpiryDateTxt { get; set; }

Html

<div class="form-group"><label asp-for="DocCatID" class="control-label control-label-left col-sm-3 text-danger">Document Category</label><div class="controls col-sm-9"><select class="form-control" asp-for="DocCatID"
               asp-items="@ViewBag.Category" data-role="select" onchange="SetExpiryDate"></select><span asp-validation-for="DocCatID" class="text-danger">@ViewBag.ErrorMsgCategory</span></div></div><div class="col-md-6"><div class="form-group"><label class="control-label control-label-left col-sm-3">Penalty Point<br />Expiry Date</label><div class="controls col-sm-9"><div class='input-group date' id='PenaltyDatePicker'><input type='text' id="txtPenaltyExpDt" asp-for="PenaltyExpDt" class="form-control disabled" /><span class="input-group-addon"><span class="glyphicon glyphicon-calendar"></span></span></div></div></div></div><div class="form-group"><label class="control-label control-label-left col-sm-3">License Expiry</label><div class="controls col-sm-9"><div class='input-group date' id='ExpiryDatePicker'><input type='text' id="txtExpiryDate" asp-for="ExpiryDate" class="form-control disabled" /><span class="input-group-addon"><span class="glyphicon glyphicon-calendar"></span></span></div></div></div>

<script>$(document).ready(function () {
$("#ExpiryDatePicker").datepicker({ format: 'dd/mm/yyyy', todayHighlight: true, autoclose: true, todayBtn: 'linked' });
$("#PenaltyDatePicker").datepicker({ format: 'dd/mm/yyyy', todayHighlight: true, autoclose: true, todayBtn: 'linked' });
function SetExpiryDate() {
    var url = '@Url.Action("GetExpiryDate", "EmpDoc")';$.post(url, $('form').serialize(), function (view) {
        console.log(view);$("#txtExpiryDate").val(view.expiryDateTxt); // Here I set the value of Date into 
                                                        textbox in dd/mm/yyyy format $("#txtPenaltyExpDt").val(view.penaltyExpDttxt);// I set the value here 
    });
    }</script>

Controller. The corresponding Expiry Dated taking from the database and set to textbox using the function  SetExpiryDate

public IActionResult GetExpiryDate(EmpDocumentModel data)
        {
            LicenseModel doc = new LicenseModel();
            var docmodel = _unitOfWork.DocumentRepository.GetExpirydate(data.EmployeeID, data.DocCatID);
            data.ExpiryDate = null;
            data.PenaltyExpDt = null;

            if (data.ExpiryDate != null)
            {
                data.ExpiryDateTxt = String.Format("{0:dd/MM/yyyy}", docmodel.ExpiryDate);
            }
            if (data.PenaltyExpDt != null)
            {
                data.PenaltyExpDttxt = String.Format("{0:dd/MM/yyyy}", docmodel.PenaltyExpDt);
            }
            return Json(data);
        }