It’s not getting a ton of press, but there’s a Cisco bug that was discovered a few months ago that will prevent the IOS from generating certificates. The patch was only release a few weeks ago, so it will be interesting to see who was paying attention.....
Certificates commonly have an expiration date. In the case of this software bug, the January 1, 2020 date was used during Cisco IOS and Cisco IOS-XE software development over 10 years ago and is a human error.