Thank you for the response.  The solution was that the directory group had to be set to 52773.  This doesn't appear in the ISC permissions guide. There are contradictions between what was pre-setup in the cloud instance and the permissions guide: https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_unix

It refers to irisowner irisusr which does not appear in /etc/passwd or /etc/group and the actual databases themselves seem to be usually set to owner:group 51773 52773 which also doesn't appear in /etc/passwd or /etc/group.