Sure, happy to. The average revocation ticket is something like https://bugzilla.mozilla.org/show_bug.cgi?id=1892419 or https://bugzilla.mozilla.org/show_bug.cgi?id=1624527. The CA shipped some kind of bug leading to noncompliance with baseline requirements. This could be anything from e.g. not validating the email address properly, inappropriately using a third-party resolver to fetch DNS names, or including some kind of extra flag set that they weren't supposed to have set. The CA doesn't want to revoke these certificates, because that would cause customers to complain:

    In response to this incident of mistaken issuance, the verification targets are all government units and government agency websites. We have assessed that the cause of this mis-issuance does not involve a key issue, but only a certificate field issue, which will not affect the customer's information security. In addition, in accordance with the administrative efficiency of government agencies, from notification to the start of processing, it requires agency supervisors at all levels. Signing and approval, and some public agencies need to find information vendors for processing, so it is difficult to complete the replacement within 5 days. Therefore, the certificate is postponed and revoked within a time limit so that the certificates of all websites can be updated smoothly.

[...]

    In this project we plan to initially issue new certificates using the same keys for users to install, and then revoke the old certificates. As these are official government websites, and considering the pressure from government agencies and public opinion, we cannot immediately revoke all certificates without compromising security. Doing so would quickly become news, and we would face further censure from government authorities.

The browsers want them to revoke the certificates immediately, because they rely on CAs to agree to the written requirements of the policy. If you issue certificates, you must validate them in precisely this way, and you must generate certificates with precisely these requirements. The CAs agree in their policies to revoke within 24 hours (serious) or 120 hours (less serious) any certificates issued that violate policy.

And yet when push comes to shove, certificates don't actually get revoked. Everybody has critical clients who pay them $$$$$ and no CAs actually want to make those clients mad. Browsers very rarely revoke certificates themselves, and realistically their only lever is to trust or distrust a CA—they need to rely on the CA to be truthful and manage their own certificates properly. They don't know exactly all of which certificates would be subject to an incident, they don't want to punish CAs for disclosing info publicly, etc. So instead, they push for systematic changes that will make it easier for CAs to revoke certificates in the future, including ACME ARI and shorter certificate lifetimes.