What's the impact of an outage like this? ACME renewals should happen daily starting 30 days before expiry so no one should have had a cert expire due to this.

What's the impact of an outage like this? ACME renewals should happen daily starting 30 days before expiry so no one should have had a cert expire due to this. New certificates wouldn't have been issued, so that's impact, although I suspect most new certs aren't taking traffic immediately (i.e. setting up a new server).