New GitHub issue #100991 from mricon:<br>
<hr>
<pre>
# Bug report
```python
import email
import email.policy
msg = email.message.EmailMessage()
msg['Message-Id'] = '<long-but-perfectly-valid-message-id-that-does-not-end-up-qp-encoded@example.com>'
msg['References'] = '<reference-to-long-but-perfectly-valid-message-id-that-gets-qp-encoded@example.com>'
msg['In-Reply-To'] = '<reference-to-long-but-perfectly-valid-message-id-that-gets-qp-encoded@example.com>'
msg.set_payload('No body')
bdata = msg.as_bytes(policy=email.policy.SMTP)
print(bdata.decode())
```
Expected output:
```
Message-Id: <long-but-perfectly-valid-message-id-that-does-not-end-up-qp-encoded@example.com>
References: <reference-to-long-but-perfectly-valid-message-id-that-gets-qp-encoded@example.com>
In-Reply-To: <reference-to-long-but-perfectly-valid-message-id-that-gets-qp-encoded@example.com>
No body
```
Actual output:
```
Message-Id: <long-but-perfectly-valid-message-id-that-does-not-end-up-qp-encoded@example.com>
References: <reference-to-long-but-perfectly-valid-message-id-th
at-gets-qp-encoded@example.com>
In-Reply-To: <reference-to-long-but-perfectly-valid-message-id-t
hat-gets-qp-encoded@example.com>
No body
```
# Your environment
- CPython versions tested on: 3.11.1
- Operating system and architecture: Fedora 37 x86_64
</pre>
<hr>
<a href="https://github.com/python/cpython/issues/100991">View on GitHub</a>
<p>Labels: type-bug</p>
<p>Assignee: </p>