selectize with maxItems > 1 not hidden on custom bootstrap 5

[Gildedter]

a selectize with maxItems > 1 is still visible when using a customized bootstrap5 theme, my only customization on bootstrap is adding additional colors for theming

// C# Code
@* Filter Field *@
<div class="row g-3 align-items-center mb-2">
    <div class="col-4">
        <label class="form-label" asp-for="@Model.Items">Items</label>
    </div>
    <div class="col-8">
        <select class="form-select" multiple asp-for="@Model.Items" placeholder="Select Items...">
            @* <option></option> *@
            <option value="0">No Item</option>
            <optgroup label="Other Crate">
                @foreach (var row in Model.ListItems)
                {
                    <option value="@r.Index">
                        @($"{row.Title} {row.Index}")
                    </option>
                }
            </optgroup>
        </select>
    </div>
</div>

...

// js code
$("#ModelItems").selectize({
    plugins: [ "remove_button" ],
    delimiter: ",",
    maxItems: 2,
    closeAfterSelect: false,
});

workarounds: add the hidden property on the original select