Oh, I can still reproduce the issue on the main branch with this patch:

diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
index cee97a8302..3f66818ae1 100644
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -4499,7 +4499,7 @@ def msg_cb(conn, direction, version, content_type, msg_type, data):
                 # server aborts connection with an error.
                 with self.assertRaisesRegex(
                     ssl.SSLError,
-                    '(certificate required|EOF occurred)'
+                    'xxxxxxxxxxxxx'
                 ):
                     # receive CertificateRequest
                     data = s.recv(1024)



$ ./python -m test test_ssl -m test_pha_required_nocert -v
(...)
FAIL: test_pha_required_nocert (test.test_ssl.TestPostHandshakeAuth)
----------------------------------------------------------------------
(...)
Traceback (most recent call last):
  File "/home/vstinner/python/main/Lib/test/test_ssl.py", line -1, in test_pha_required_nocert
AssertionError: (...)
...


=> "line -1"