Since contents of certificates contents sadly often diff there was a ballot to streamline the contents to lessen the burden on implementations to interpret the differences.

Entrust missed/ignored the updates to how certificates were supposed to be formed and when caught declined to revoke the incorrectly issued ones (because it's probably a more or less manual process for many admins working in a pre-Let's Encrypt style of fashion) and they didn't want to inconvenience their customers and assumed that they themselves were the important party in the equation (CA's was that historically compared to site-admins).

The certificate industry has always been quite ad-hoc with CA's being entitled middlemen, we have Let's Encrypt and almost ubiquitous encryption now because browser makers and other internet actors saw security as more important than protecting the CA's business and now that LE is established Google,etc aren't the slightest interested in pampering CAs if they aren't interested in cleaning up the system.