OpenShift 4.13 removed code that allowed customers to:

• Install OpenShift via IPI on GCP with Shared VPC (XPN)
• DNS must be in a separate Service Project

This allowed them to acheive:

• Separation of duties and responsibilities in GCP design
• Simplify DNS peering relationships within my Shared VPC
• This would be a reversal of https://issues.redhat.com/browse/CORS-2474 which introduced breaking changes between OCP 4.12 and OCP 4.13 for many customers.
• This would enable customers in GCP Shared VPC to take advantage of RHACM for automated cluster deployments.

Engineering Details:

• This would reverse https://github.com/openshift/installer/pull/6771 which states "If this is needed, then it can always be added back"
• I'm filing this as a bug, because it's a breaking change from the behavior in the 4.12 tech preview. While TP expectations may change over time, this deployment type is not uncommon and we will experience as more customers deploy in GCP.