core healthchecks randomly fails with TaskCanceledException or OperationCanceledException

I've finally found answer.

The initial reason is that when HTTP request is aborted, then httpContext.RequestAborted CancellationToken is triggered, and it throws exception (OperationCanceledException).

I have global exception handler in my application, and I have been converting every unhandled exception to 500 error. Even though client aborted request, and never got the 500 response, my logs kept logging this.

The solution I implemented is like that:

public async Task Invoke(HttpContext context)
        await _next(context);
    catch (Exception ex)
        if (context.RequestAborted.IsCancellationRequested)
            _logger.LogWarning(ex, "RequestAborted. " + ex.Message);

        _logger.LogCritical(ex, ex.Message);
        await HandleExceptionAsync(context, ex);

private static Task HandleExceptionAsync(HttpContext context, Exception ex)
    var code = HttpStatusCode.InternalServerError; // 500 if unexpected

    //if (ex is MyNotFoundException) code = HttpStatusCode.NotFound;
    //else if (ex is MyUnauthorizedException) code = HttpStatusCode.Unauthorized;
    //else if (ex is MyException) code = HttpStatusCode.BadRequest;

    var result = JsonConvert.SerializeObject(new { error = ex.Message });
    context.Response.ContentType = "application/json";
    context.Response.StatusCode = (int)code;
    return context.Response.WriteAsync(result);

hope it helps to somebody.