This is a clone of issue OCPBUGS-19444. The following is the description of the original issue:
—
When we Load the AgentClusterInstall manifest from disk, we sometimes make changes to it.

e.g. after the fix for OCPBUGS-7495 we rewrite any lowercase platform name to mixed case, because for a while we required lowercase even when mixed case is correct.

In 4.14, we set the userManagedNetworking to true when platform:none is used, even if the user didn't specify it in the ZTP manifests, because the controller in ZTP similarly defaults it.

However, these changes aren't taking effect, because they aren't passed through to the manifest that is included in the Agent ISO.