IBM Cloud relies on a static hard coded list of support Regions for IPI. However, whenever a new Region becomes available, it cannot be used until it is added to this list of available Regions.
https://github.com/openshift/installer/blob/13932601852174e4294e16ff9cfca7df082f1ce0/pkg/types/ibmcloud/validation/platform.go#L15-L30 

4.19.0

100%

    1. Create install-config for IBM Cloud
    2. Specify a newly available Region (e.g., ca-mon)
    3. Attempt to create manifests

ERROR failed to fetch Master Machines: failed to load asset "Install Config": failed to create install config: invalid "install-config.yaml" file: platform.ibmcloud.region: Unsupported value: "ca-mon": supported values: "eu-gb", "jp-tok", "au-syd", "ca-tor", "jp-osa", "br-sao", "us-south", "us-east", "eu-de", "eu-es"

Successful cluster creation

Rather than keep updating this static list, it would be better if the Regions could be looked up dynamically, to provide to the install-config creation path. Thus, validation for the Region would not be necessary in that case.

For instance current regions:

Listing regions...


Name            Show name
au-syd          Sydney (au-syd)
in-che          Chennai (in-che)
jp-osa          Osaka (jp-osa)
jp-tok          Tokyo (jp-tok)
eu-de           Frankfurt (eu-de)
eu-es           Madrid (eu-es)
eu-gb           London (eu-gb)
ca-mon          Montreal (ca-mon)
ca-tor          Toronto (ca-tor)
us-south        Dallas (us-south)
...