fetch failed: unable to verify the first certificate

Bug Description

I'm getting the error fetch failed: unable to verify the first certificate when providing a CA certificate to the dispatcher option. I've written the exact same procedure in the axios project and it's working as expected.

import { fetch, Agent as UndiciAgent } from "undici";

const response = await fetch(myUrl, {
  method: "POST",
  body: JSON.stringify({ endUserIp: ip }),
  dispatcher: new UndiciAgent({
    connect: {
      pfx: pfx,
      passphrase: "qwerty123",
      ca: testCA,
    },
  }),
  headers: { "Content-Type": "application/json" },
});

const client = axios.create({
  httpsAgent: new Agent({ pfx, passphrase: "qwerty123", ca: testCA }),
  headers: {
    "Content-Type": "application/json",
  },
});
const response = await client.post(myUrl, {
  endUserIp: ip,
});

Environment

Windows 11
Node v18.16.1

The payload names the dispatcher option and its TLS connect settings but no source file or test. Start by reproducing the fetch example on Node v18.16.1 with the supplied pfx, passphrase, and CA, then trace the dispatcher’s certificate handling; done means the reported configuration verifies successfully and the behavior is covered by a regression test.