n3t_admin
this not being fixed hours later is the true amateurism.
The issue should be detected by uptime checks warning the system administrators prior to it causing downtime. The issue leading to rotation breaking should cause alerts, not downtime. This is one of the most basic things to check for uptime monitoring along with checking for domain expiry via RDAP (previously WHOIS which is deprecated and being rapidly phased out).
They say they already have the new certs, so why not enable them?
Their rotation scripting must be broken. It's likely they made changes to it but didn't test it properly. That has happened to us before such as certbot making changes incompatible with our systemd unit hardening changes but it hasn't caused any downtime because we have monitoring for our services which warns us if the certificates they're using are going to expire soon. We get alerts which are publicly visible in our infrastructure channel, not downtime. We do the same for domain expiry in case something breaks auto-renewal.