On 01/16/2018 11:15 PM, teor wrote:
- it stops publishing an IPv6 ORPort or IPv4 DirPort,
for one or more consensuses, even if it changes back.
Ick, that was it. There was an attempt by me to close ports 80 and 443 of IPv6 for 1 minute to let certbot try to renew the LetsEncrypt certificate over IPv6.