Browser tests crash opening not found URL

I have this patch:

diff --git a/Products/CMFPlone/tests/test_redirect_after_login.py b/Products/CMFPlone/tests/test_redirect_after_login.py
index 4552a508d..ab33a7a91 100644
--- a/Products/CMFPlone/tests/test_redirect_after_login.py
+++ b/Products/CMFPlone/tests/test_redirect_after_login.py
@@ -205,6 +205,10 @@ class TestRedirectAfterLogin(unittest.TestCase):
             "Logout status message not displayed.",
         )
 
+    def test_zzzz(self):
+        breakpoint()
+        self.browser.open('http://nohost/plone/bogus')
+
     def test_password_reset_uses_all_adapters(self):
         # By default, when you reset your password, you are directly logged in.
         # An initial login adapter should be active.

When I run the silly test_zzzz with buildout.coredev I see:

(Pdb++) self.browser
<plone.testing._z2_testbrowser.Browser object at 0x7ff86590aa90>
(Pdb++) self.browser.open('http://nohost/plone/bogus')
*** ZODB.POSException.ConnectionStateError: Shouldn't load state for persistent.list.PersistentList 0x3b676fdf706dc1a7 when the connection is closed
Traceback (most recent call last):
  File "/home/ale/.buildout/eggs/cp311/zope.testbrowser-5.6.1-py3.11.egg/zope/testbrowser/browser.py", line 256, in open
    self._processRequest(url, make_request)
  File "/home/ale/.buildout/eggs/cp311/zope.testbrowser-5.6.1-py3.11.egg/zope/testbrowser/browser.py", line 282, in _processRequest
    resp = make_request(reqargs)
  File "/home/ale/.buildout/eggs/cp311/zope.testbrowser-5.6.1-py3.11.egg/zope/testbrowser/browser.py", line 253, in make_request
    return self.testapp.get(url, **args)
  File "/home/ale/.buildout/eggs/cp311/WebTest-3.0.0-py3.11.egg/webtest/app.py", line 324, in get
    return self.do_request(req, status=status,
  File "/home/ale/.buildout/eggs/cp311/zope.testbrowser-5.6.1-py3.11.egg/zope/testbrowser/browser.py", line 93, in do_request
    response = super(TestbrowserApp, self).do_request(req, status,
  File "/home/ale/.buildout/eggs/cp311/WebTest-3.0.0-py3.11.egg/webtest/app.py", line 620, in do_request
    res = req.get_response(app, catch_exc_info=True)
  File "/home/ale/.buildout/eggs/cp311/WebOb-1.8.7-py3.11.egg/webob/request.py", line 1309, in send
    status, headers, app_iter, exc_info = self.call_application(
  File "/home/ale/.buildout/eggs/cp311/WebOb-1.8.7-py3.11.egg/webob/request.py", line 1278, in call_application
    app_iter = application(self.environ, start_response)
  File "/home/ale/.buildout/eggs/cp311/WebTest-3.0.0-py3.11.egg/webtest/lint.py", line 196, in lint_app
    iterator = application(environ, start_response_wrapper)
  File "/home/ale/.buildout/eggs/cp311/plone.testing-8.0.3-py3.11.egg/plone/testing/_z2_testbrowser.py", line 39, in wrapped_func
    return func(*args, **kw)
  File "/home/ale/.buildout/eggs/cp311/plone.testing-8.0.3-py3.11.egg/plone/testing/_z2_testbrowser.py", line 66, in __call__
    wsgi_result = publish(environ, start_response)
  File "/home/ale/Code/plone/projects/coredev/6.1/src/Zope/src/ZPublisher/WSGIPublisher.py", line 405, in publish_module
    request.close()
  File "/home/ale/Code/plone/projects/coredev/6.1/src/Zope/src/ZPublisher/BaseRequest.py", line 215, in close
    notify(EndRequestEvent(None, self))
  File "/home/ale/.buildout/eggs/cp311/zope.event-4.6-py3.11.egg/zope/event/__init__.py", line 33, in notify
    subscriber(event)
  File "/home/ale/.buildout/eggs/cp311/zope.component-5.1.0-py3.11.egg/zope/component/event.py", line 27, in dispatch
    component_subscribers(event, None)
  File "/home/ale/.buildout/eggs/cp311/zope.component-5.1.0-py3.11.egg/zope/component/_api.py", line 134, in subscribers
    return sitemanager.subscribers(objects, interface)
  File "/home/ale/.buildout/eggs/cp311/zope.interface-6.0-py3.11-linux-x86_64.egg/zope/interface/registry.py", line 445, in subscribers
    return self.adapters.subscribers(objects, provided)
  File "/home/ale/.buildout/eggs/cp311/zope.interface-6.0-py3.11-linux-x86_64.egg/zope/interface/adapter.py", line 892, in subscribers
    subscriptions = self.subscriptions([providedBy(o) for o in objects], provided)
  File "/home/ale/.buildout/eggs/cp311/zope.interface-6.0-py3.11-linux-x86_64.egg/zope/interface/adapter.py", line 874, in _uncached_subscriptions
    if order >= len(byorder):
  File "/usr/lib/python3.11/collections/__init__.py", line 1235, in __len__
    return len(self.data)
  File "/home/ale/.buildout/eggs/cp311/ZODB-5.8.0-py3.11.egg/ZODB/Connection.py", line 782, in setstate
    raise ConnectionStateError(msg)

Reproduce the failure with test_zzzz in Products/CMFPlone/tests/test_redirect_after_login.py and trace the request through plone/testing/_z2_testbrowser.py, especially the request.close path shown in the traceback. Done means opening the bogus URL no longer raises ZODB.POSException.ConnectionStateError in the browser test.