Using the same registry, oc and oc-mirror 4.16 versions but different installer versions in different directory structures, 4.16 returns the following error while generating the ISO file while 4.14 does not:

DEBUG Using internal constant for release image quay.io/openshift-release-dev/ocp-release@sha256:0e71cb61694473b40e8d95f530eaf250a62616debb98199f31b4034808687dae 
ERROR Release Image arch could not be found: command '[oc adm release info quay.io/openshift-release-dev/ocp-release@sha256:0e71cb61694473b40e8d95f530eaf250a62616debb98199f31b4034808687dae -o=go-template={{if and .metadata.metadata (index . "metadata" "metadata" "release.openshift.io/architecture")}}{{index . "metadata" "metadata" "release.openshift.io/architecture"}}{{else}}{{.config.architecture}}{{end}} --insecure=true --registry-config=/tmp/registry-config2248417039]' exited with non-zero exit code 1:  
ERROR error: unable to read image quay.io/openshift-release-dev/ocp-release@sha256:0e71cb61694473b40e8d95f530eaf250a62616debb98199f31b4034808687dae: Get "http://quay.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers) 
ERROR                                              
WARNING Unable to validate the release image architecture, skipping validation

This is valid for disconnected environments. This doesn't affect creating the image, it's more a cosmetic error. The ISO file is still being created and works as expected.

openshift-install-linux-4.16

./openshift-install agent create image --dir=./abi/ --log-level=debug

1. Create 2 directory structures ocp4.14 and ocp4.16
2. Get from mirror.openshift.com oc client, oc-mirror for OCP 4.16 and openshift-install for both 4.14 and 4.16
3. Clone catalogs for both versions 4.14 and 4.16 to private registry
4. Use same install-config.yaml and agent-config.yaml for both "openshift-install agent create image" command with different versions

Error shows up for version 4.16

No error should show as in version 4.14

There are logs and config files in linked case.
I'm attaching here the files and logs from my own reproduction.