TryParseValueFromString not triggered - no validation message output

Based on the Blazor University tutorials and many SO/GitHub posts I am trying to create a custom component that inherits from InputBase<int?>.

It displays fine, but on submission the custom validation method TryParseValueFromString() does not fire and so my validation messages are not bubbling up into the edit context, nor displaying:

Setting a breakpoint in the method body further proves the method is never triggering as the breakpoint is never hit.

In time this will have complex validation, so I cannot rely on DataAnnotations validation to provide these checks and want to better understand TryParseValueFromString().

Can somebody please advise how to get the above method to trigger for a non-parseable value?

Page code

@page "/"@using BlazorAppTryParseValueFromString.Component@using static Microsoft.AspNetCore.Components.Web.RenderMode@rendermode InteractiveServer<PageTitle>Index</PageTitle><EditForm Model="myModel" OnValidSubmit="FormSubmit"><ValidationSummary /><p><IntegerComponent @bind-Value=myModel.MyNumber /></p><p><input type="submit" value="Go" /><ValidationMessage For="() => myModel.MyNumber" /></p><p>        @Result</p></EditForm>@code {    public class MyModel    {        public int? MyNumber { get; set; }    }    public string Result { get; set; } = "";    public MyModel myModel { get; set; } = new();    public async void FormSubmit()    {        string yourNumber = myModel.MyNumber.HasValue ? myModel.MyNumber.Value.ToString() : "nothing";        Result = $"Your number was {yourNumber}";    }}

Component code

@inherits InputBase<int?><div><input type="text" @bind=CurrentValue /></div>@code {    protected override bool TryParseValueFromString(string? value, out int? result, out string validationErrorMessage)    {        validationErrorMessage = "";        result = null;        if (string.IsNullOrWhiteSpace(value))        {            return true;        }        int parsedInt;        if (!int.TryParse(value.Trim(), out parsedInt))        {            validationErrorMessage = "Invalid value!";            return false;        }        result = parsedInt;        return true;    }}

Updates

1. Added the tutorial file from Blazor University to my project, and that same method doesn't get triggered there either. This would appear to be a wider-scale issue therefore.
2. Created a new Blazor Server project type (native .Net8) in VS2022 and added the same page. Same failure occurs.