When we introduced aarch64 support for IPI on Azure, we changed the Installer from using managed images (no architecture support) to using Image Galleries (architecture support). This means that the place where the Installer looks for rhcos bootimages has changed from "/resourceGroups/$rg_name/providers/Microsoft.Compute/images/$cluster_id" to "/resourceGroups/$rg_name/providers/Microsoft.Compute/galleries/gallery_$cluster_id/images/$cluster_id/versions/$rhcos_version".
This has been properly handled in the IPI workflow, with changes to the terraform configs [1]. However, our ARM template for UPI installs [2] still uploads images via Managed Images and therefore breaks workflows provisioning compute nodes with MAO.

[1] https://github.com/openshift/installer/pull/6304
[2] https://github.com/openshift/installer/blob/release-4.12/upi/azure/02_storage.json

4.13 and 4.12

always

Any workflow that provisions compute nodes with MAO. For example, in the UPI deploy with ARM templates:
1. Execute 06_workers.json template with compute.replicas: 0 in the install-config, then run the oc scale command to "activate" MAO provision (`oc scale --replicas=1 machineset $machineset_name -n openshift-machine-api`)
2. Skip 06_workers.json but set compute.replicas: 3 in the install-config. MAO will provision nodes as part of the cluster deploy.

Error Message:           failed to reconcile machine 
"maxu-upi2-gc7n8-worker-eastus3-68gdx": failed to create vm 
maxu-upi2-gc7n8-worker-eastus3-68gdx: failure sending request for 
machine maxu-upi2-gc7n8-worker-eastus3-68gdx: cannot create vm: 
compute.VirtualMachinesClient#CreateOrUpdate: Failure sending request: 
StatusCode=404 -- Original Error: Code="GalleryImageNotFound" 
Message=""The gallery image 
/subscriptions/53b8f551-.../resourceGroups/maxu-upi2-gc7n8-rg/providers/Microsoft.Compute/galleries/gallery_maxu_upi2_gc7n8/images/maxu-upi2-gc7n8-gen2/versions/412.86.20220930
 is not available in eastus region. Please contact image owner to 
replicate to this region, or change your requested region."" 
Target="imageReference"

But the image can be found at:
/subscriptions/53b8f551-.../resourceGroups/maxu-upi2-gc7n8-rg/providers/Microsoft.Compute/images/maxu-upi2-gc7n8-gen2

No errors and the bootimage is loaded from the Image Gallery.

02_storage.json template will have to be rewritten to use Image Gallery instead of Managed Images.