LMAO:

"The CRL's were signed with the original private keys (which were supposed to be the correct keys with appropriate entropy) but given that this resulted in incorrect signatures, they were resigned with flawed keys."

So they got failed signatures from using the correct keys to sign the CSRs rather than the corrupted ones, but then rather than realizing something was seriously messed up and aborting, they just threw away the good signatures and re-signed with the corrupted keys to get it to pass. 🤦

Source: https://bugzilla.mozilla.org/show_bug.cgi?id=2083449#c11