We have an OKD 4.12 cluster which has persistent and 
increasing ingresswithoutclassname alerts with no ingresses normally 
present in the cluster. I believe the ingresswithoutclassname being 
counted is created as part of the ACME validation process managed by the
 cert-manager operator with it's openshift route addon which are torn down once the ACME validation is complete.

 4.12.0-0.okd-2023-04-16-041331

seems very consistent. went away during an update but came back shortly after and continues to increase.

1. create ingress w/o classname
2. see counter increase
3. delete classless ingress
4. counter does not decrease.

https://github.com/openshift/cluster-ingress-operator/issues/912