Answer
This is a deployment-ordering problem — the custom field configuration needs to reach the database (via a delivery/publish step) before the IAL that depends on its generated _CFV view is deployed, and by default there's no guarantee the two happen in that order together. The practical fix is to explicitly sequence them: publish/deploy the custom field configuration first (as its own script or .ins file), then deploy the IAL afterward — in Cloud, since install.tem itself can't be modified, this means writing separate scripts for the custom field (published first) and the IAL, and listing them in the correct order in deploy.ini, rather than relying on both being deployed together in a single automated step without explicit ordering.