Cannot POST to worker service

app.get('/test', (c) => {
  return c.text('GET /test')
})

app.post('/test', (c) => {
  return c.text('POST /test')
})

app.get('/test', async (c) => {
  return await c.env.WORKER_A.fetch(c.req) // 'GET /test'
})

app.post('/test', async (c) => {
  return await c.env.WORKER_A.fetch(c.req)
})

Trace: TypeError: Cannot construct a Request with a Request object that has already been used.
    at new Request (/Users/polt/aces-workers/auth-test/node_modules/undici/lib/fetch/request.js:488:15)
    at new Request (/Users/polt/aces-workers/auth-test/node_modules/@miniflare/core/src/standards/http.ts:393:13)
    at upgradingFetch (/Users/polt/aces-workers/auth-test/node_modules/@miniflare/web-sockets/src/fetch.ts:21:19)
    at WebSocketPlugin.<anonymous> (/Users/polt/aces-workers/auth-test/node_modules/@miniflare/core/src/standards/http.ts:891:21)
    [TRUNCATED}