I can confirm too in Plone 5.2.8 pinning waitress = 2.1.2 fixes the Bad file descriptor error. But Client disconnected while serving is still an issue. See Waitress "Client disconnected while serving" and "Bad file descriptor".
I can confirm too in Plone 5.2.8 pinning waitress = 2.1.2 fixes the Bad file descriptor error. But Client disconnected while serving is still an issue. See Waitress "Client disconnected while serving" and "Bad file descriptor".