When using IPI for IBM Cloud to create a Private BYON cluster, the installer attempts to fetch the VPC resource to verify if it is already a PermittedNetwork for the DNS Services Zone.
However, currently there is a new VPC Region that is listed in IBM Cloud, eu-es, which is not yet GA'd. This means while it is listed in available VPC Regions, to search for resources, requests to eu-es fail. Any attempts to use VPC Regions alphabetically after eu-es (appears they are returned in this order), fail due to requests made to eu-es. This includes, eu-gb, us-east, and us-south, causing a golang panic.

4.12

100%

1. Create IBM Cloud BYON resources in us-east or us-south
2. Attempt to create a Private BYON based cluster in us-east or us-south

DEBUG   Fetching Common Manifests...               
DEBUG   Reusing previously-fetched Common Manifests 
DEBUG Generating Terraform Variables...            
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x2bdb706]

goroutine 1 [running]:
github.com/openshift/installer/pkg/asset/installconfig/ibmcloud.(*Metadata).IsVPCPermittedNetwork(0xc000e89b80, {0x1a8b9918, 0xc00007c088}, {0xc0009d8678, 0x8})
	/go/src/github.com/openshift/installer/pkg/asset/installconfig/ibmcloud/metadata.go:175 +0x186
github.com/openshift/installer/pkg/asset/cluster.(*TerraformVariables).Generate(0x1dc55040, 0x5?)
	/go/src/github.com/openshift/installer/pkg/asset/cluster/tfvars.go:606 +0x3a5a
github.com/openshift/installer/pkg/asset/store.(*storeImpl).fetch(0xc000ca0d80, {0x1a8ab280, 0x1dc55040}, {0x0, 0x0})
	/go/src/github.com/openshift/installer/pkg/asset/store/store.go:227 +0x5fa
github.com/openshift/installer/pkg/asset/store.(*storeImpl).Fetch(0x7ffd948754cc?, {0x1a8ab280, 0x1dc55040}, {0x1dc32840, 0x8, 0x8})
	/go/src/github.com/openshift/installer/pkg/asset/store/store.go:77 +0x48
main.runTargetCmd.func1({0x7ffd948754cc, 0xb})
	/go/src/github.com/openshift/installer/cmd/openshift-install/create.go:261 +0x125
main.runTargetCmd.func2(0x1dc38800?, {0xc000ca0a80?, 0x3?, 0x3?})
	/go/src/github.com/openshift/installer/cmd/openshift-install/create.go:291 +0xe7
github.com/spf13/cobra.(*Command).execute(0x1dc38800, {0xc000ca0a20, 0x3, 0x3})
	/go/src/github.com/openshift/installer/vendor/github.com/spf13/cobra/command.go:876 +0x67b
github.com/spf13/cobra.(*Command).ExecuteC(0xc000bc8000)
	/go/src/github.com/openshift/installer/vendor/github.com/spf13/cobra/command.go:990 +0x3bd
github.com/spf13/cobra.(*Command).Execute(...)
	/go/src/github.com/openshift/installer/vendor/github.com/spf13/cobra/command.go:918
main.installerMain()
	/go/src/github.com/openshift/installer/cmd/openshift-install/main.go:61 +0x2b0
main.main()
	/go/src/github.com/openshift/installer/cmd/openshift-install/main.go:38 +0xff

Successful Private cluster creation using BYON on IBM Cloud

IBM Cloud development has identified the issue and is working on a fix to all affected supported releases (4.12, 4.13, 4.14+)