Edge Functions - inconsistent results when running .invoke locally using supabase serve

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
}

export function createHandler(tasks = originalTasks) {
  return async function (req: Request) {
    if (req.method !== 'POST') {
      console.log(`Method not allowed: ${req.method}`);
      return new Response(JSON.stringify({ error: 'Method not allowed' }), {
        headers: { ...corsHeaders, 'Allow': 'POST' },
        status: 405,
      });
    }

    return new Response(JSON.stringify('hello'), {
      headers: { ...corsHeaders, 'Content-Type': 'application/json' },
      status: 200,
    });
  };
}

Deno.test('[Unit Test] Method Not POST', {sanitizeOps:false, sanitizeResources:false}, async () => {  
  // Switch to anon client
  const anonClient = createClient<Database>(supabaseUrl, anonKey, options);

  // Invoke the 'order' function without the first name
  const { data, error } = await anonClient.functions.invoke('update-system-settings-handler', {
    method: 'PUT',
    headers: { Authorization: `Bearer ${anonKey}`},
    body: { }
  });

  // log the error message
  const errorMessage = (await error.context.json()).error;
  console.log(`message: ${errorMessage}`);
  console.log(`status: ${await error.context.status}`);
  console.log(`headers: ${await error.context.headers.get('Allow')}`);

  // Check for errors from the function invocation
  if (data || !error || errorMessage != 'Method not allowed' || error.context.status != 405 || error.context.headers.get('Allow') != 'POST') {
    assert(false);
  }
});