tag helper asp-route- not working - Razor Pages (.Net Core 3 preview 5)

I am prety new to Razor Pages so maybe I am doing it just wrong. I am using .Net Core 3 preview 5 and for some reason my asp-route parameter is not working.

I have the following button in my cshtml (index) page:

<form method="get" asp-page-handler="RetrieveData" asp-route-retrieveid="5">
    <button class="btn btn-primary">Retrieve Data</button>
</form>

My code behind for this action:

public async Task<IActionResult> OnGetRetrieveData(int retrieveid)
{
    // Do stuff
    return Page();
}

Everytime I press the button the retrieveid parameter remains 0 (null):

My entire cshtml code:

@page "{handler?}"
@model IndexModel
@{
    ViewData["Title"] = "Retrieve Data";
}

@section Scripts
{
    <script type="text/javascript">
        // Some jQuery
    </script>
}


<div class="text-center">
    <h1 class="display-4">Retrieve Data</h1>
</div>



@if (Model.ErrorMessage != null)
{
    <div id="ErrorMsg" class="alert alert-info alert-dismissible fade show" role="alert">
        @Model.ErrorMessage
        <button type="button" class="accept-policy close" data-dismiss="alert" aria-label="Close" data-cookie-string="@Model.ErrorMessage">
            <span aria-hidden="true">Sluiten</span>
        </button>
    </div>
}



<button id="getData" class="btn btn-primary" data-toggle="modal" data-target="#modalGetDataConfirm">
    Get Data
</button>



<!-- Modal -->
<div id="modalGetDataConfirm" class="modal fade" role="dialog">
    <div class="modal-dialog">

        <!-- Modal content-->
        <div class="modal-content">
            <div class="modal-header">
                <h4 class="modal-title">Get Data</h4>
                <button type="button" class="close" data-dismiss="modal">&times;</button>
            </div>

            <div class="modal-body">
                <p>Do you want to retrieve the data</p>
            </div>

            <div class="modal-footer">
                <form method="get" asp-page-handler="RetrieveData" asp-route-retrieveid="5">
                    <button class="btn btn-primary">Retrieve Data</button>
                </form>
                <button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>
            </div>
        </div>
    </div>
</div>



<br />


@if (Model.DataModel != null)
{

    // table with search and the retrieved data


    var prevDisabled = !Model.DataModel.HasPreviousPage ? "disabled" : "";
    var nextDisabled = !Model.DataModel.HasNextPage ? "disabled" : "";

    <a asp-page-handler="LoadData"
       asp-route-sortOrder="@Model.CurrentSort"
       asp-route-pageIndex="@(Model.DataModel.PageIndex - 1)"
       asp-route-currentFilter="@Model.CurrentFilter"
       class="btn btn-default @prevDisabled">
        Vorige
    </a>
    <a asp-page-handler="LoadData"
       asp-route-sortOrder="@Model.CurrentSort"
       asp-route-pageIndex="@(Model.DataModel.PageIndex + 1)"
       asp-route-currentFilter="@Model.CurrentFilter"
       class="btn btn-default @nextDisabled">
        Volgende
    </a>

}

The strange thing is that the asp-route values in the paging <a> element IS working..