Has anyone in the team had a look?  If it's working for others in the same circumstances (I'm also using Razor Pages, rather than straight MVC), then at least I can try digging in to that or I can create a small example that reproduces the problem.  If not, it would be great to know whether it's being looked into.

I took this from the tutorial sample on https://docs.microsoft.com/en-gb/aspnet/core/tutorials/razor-pages/razor-pages-start?view=aspnetcore-3.1.  I modified the project to include newer versions of jquery and jquery.ui, then added the packages for igniteUI and Infragistics.Web.AspNetCore.  

I changed the Create.cshtml page to use IgniteUI controls instead of the default input controls.

I was using the infragistics css and js locally, but I removed them from the zipped sample to conserve space.

@page
@using Infragistics.Web.Mvc;
@model RazorPagesMovie.Pages.Movies.CreateModel

@{
    ViewData["Title"] = "Create";
}

<link type="text/css" href="@Url.Content("~/css/themes/infragistics/infragistics.theme.css")" rel="stylesheet" />
<link type="text/css" href="@Url.Content("~/css/structure/infragistics.css")" rel="stylesheet" />

<script type="text/javascript" src="~/lib/jquery/dist/modernizr.min.js"></script>
<script type="text/javascript" src="~/lib/jquery/dist/jquery.min.js"></script>
<script type="text/javascript" src="~/lib/jquery/dist/jquery-ui.min.js"></script>
<script type="text/javascript" src="~/js/infragistics.core.js"></script>
<script type="text/javascript" src="~/js/infragistics.lob.js"></script>
<script type="text/javascript" src="~/js/modules/i18n/regional/infragistics.ui.regional-en.js"></script>

<h1>Create</h1>

<h4>Movie</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form method="post">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <div class="form-group">
                <label asp-for="Movie.Title" class="control-label"></label>
                <div>
                    @(Html.Infragistics().TextEditorFor(model => model.Movie.Title)
                       .ID("TitleEditor")
                       .InputName("TitleInput")
                       .PlaceHolder("Movie Title")
                       .Render()
                    )
                </div>
                <span asp-validation-for="Movie.Title" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Movie.ReleaseDate" class="control-label"></label>
                <div>
                    @(Html.Infragistics().DatePickerFor(model => model.Movie.ReleaseDate)
                                 .ID("datePicker")
                                 .Render())
                </div>
                <span asp-validation-for="Movie.ReleaseDate" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Movie.Genre" class="control-label"></label>
                <div>
                    @(Html.Infragistics().TextEditorFor(model => model.Movie.Genre)
                       .ID("GenreEditor")
                       .InputName("GenreInput")
                       .PlaceHolder("Genre")
                       .Render()
                    )
                </div>
                <span asp-validation-for="Movie.Genre" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Movie.Price" class="control-label"></label>
                <div>
                    @(Html.Infragistics().NumericEditorFor(model => model.Movie.Price)
                          .ID("priceEditor")
                          .DataMode(NumericEditorDataMode.Double)
                          .MinValue(0)
                          .MaxDecimals(2)
                          .Value(0)
                          .Width(120)
                          .Render())
                </div>
                <span asp-validation-for="Movie.Price" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Movie.Rating" class="control-label"></label>
                <div>
                    @(Html.Infragistics().TextEditorFor(model => model.Movie.Rating)
                          .ID("ratingEditor")
                          .Render())
                </div>
                <span asp-validation-for="Movie.Rating" class="text-danger"></span>
            </div>
            <div class="form-group">
                <input type="submit" value="Create" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>

<div>
    <a asp-page="Index">Back to List</a>
</div>

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

Please let me know if you're able to run, and to reproduce my problem.  In this case, the first four items generated by the helpers did not bind properly to the model.

The zipped solution is at the following link.  The LocalDB may need to be recreated with Update-Database in the package manager console.

Onedrive zipfile link