I spotted this paper, "Revocation Statuses on the Internet" by Korzhitskii and Carlsson, being discussed on Twitter. It covers measurements of PKI revocation generally and Let's Encrypt's response to the 2020.02.29 CAA Rechecking Bug specifically. It's an interesting read overall but this part from §4.2 stood out to me as particularly cool and worthy of praise:
While we only had timeouts for 0.04% of the status requests, the differences between the number of affected certificates were substantial between CAs: only 0.07% of the Let’s Encrypt certificates had at least one timeout, compared to 13.98% of the other CAs’ certificates. These fractions are non-negligible, since most browsers soft-fail on an OCSP timeout and continue to establish a potentially insecure connection
It's not easy running a reliable OCSP service. Doubly so at the scale Let's Encrypt issues at. Kudos to everyone for delivering excellent reliability through a particularly tumultuous revocation event and beyond.