When upgrading from 4.11 to 4.12, Ingress config acquires two new fields:

domain:   <------- new
loadBalancer:  <------- new
apiVersion: config.openshift.io/v1
kind: Ingress

From relevant team:
> I believe the real source of the issue is that on upgrade from 4.11 - 4.12 the ingress operator is not populating these new fields from the ingress controller config. These fields are only updated when a new ingress-controller config is created and not on an existing one.

> Ingress controller config in 4.11 and is generated from the ingress config in 4.12.

4.12.18 specifically
4.12.x  presumably

All cluster upgrades from 4.11.20 to 4.12.18 without domain set

1. Create 4.11.20 cluster
2. Ensure cluster does not have `domain` nor `loadBalancer` parameters set in Ingress config
3. Upgrade cluster to 4.12.18

Cluster blocks mid-upgrade as oauth and console pods cannot rollout

Cluster upgrades without incident

Issue filed on behalf of consultant