Confusing and Conflicting Date Conundrum

I have a model including two different dates.  Both these dates are set up similar to each other in the model.

[Required]
        [Display(Name = "Booking Date")]
        [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:D}")]

        public DateTime BookingDate { get; set; }

       ....

        [Display(Name = "Invoice Date")]
        [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:D}")]
        public DateTime? InvoiceDate { get; set; }

I have then created a view component, including these dates.

 public IViewComponentResult Invoke(int id)
        {
            var jobs = from j in ctx.Job
                       .Include(j => j.Site)
                       .Include(j => j.WaterBody)
                       .Where(j => j.Site.SiteID == id && j.InvoiceDate != null)
                       .OrderByDescending(j => j.BookingDate)
                       .Take(6)
                       select j;

            return View(jobs);
        }

I assume the rest of the view component isn't relevant.

Then in the default view I have:

 @foreach (var j in Model)
        {<tr><td>

                    @j.BookingDate.ToString("dd MM yyyy")</td><td>
                    @j.JobDescription.Substring(0, Math.Min(j.JobDescription.Length, 38))</td><td>
                    @j.InvoiceDate</td><td><a asp-controller="Jobs"
                       asp-action="Details"
                       asp-route-id="@j.JobID">More Details</a></td></tr>

        }

All I want to do is format Invoice date the same as Booking Date.  However every time I try it is throwing an error.  It makes no sense.  Why would one take the ToString Argument happily and the other refuse it?  How can I get this date to play along?  Why am I having to format the dates at all given they are formatted already in the Model?