Icinga 2 v2.8.0 through v2.11.7 and v2.12.2 has an issue where revoked certificates due for renewal will automatically be renewed, ignoring the CRL. This issue is fixed in Icinga 2 v2.11.8 and v2.12.3.
https://github.com/Icinga/icinga2/security/advisories/GHSA-pcmr-2p2f-r7j6