Let's Encrypt was made aware via internal alerting received on 2026-06-03 at 06:31 UTC that a database replication issue caused recently-added CRL entries to be temporarily omitted from published CRLs before their respective certificates’ expirations. Subsequent CRL updates correctly contain the affected entries.
We have filed a preliminary incident report at 2044788 - Let's Encrypt: CRLs Temporarily Missing Revoked Serials.