Alter Edge does not appear to work

In issuing a command to add a pair to an existing edge in GSQL:
ALTER EDGE CREATED_IN ADD PAIR (FROM PRMGroup, TO PRMNamespace)

The command seems to be successful, no errors are shown. However, doing an ls command shows the pairs were not added. Running them in a schema change job does result in errors. Example job:

BEGIN
CREATE SCHEMA_CHANGE JOB prmEdgeTest FOR GRAPH rcarpentinsights {
    ALTER EDGE CREATED_IN ADD PAIR (FROM PRMGroup, TO PRMNamespace);
    ALTER EDGE CREATED_IN ADD PAIR (FROM PRMResource, TO PRMNamespace);
    ALTER EDGE CREATED_IN ADD PAIR (FROM PRMNamespaceGroup, TO PRMNamespace);
    ALTER EDGE HAS_ACCESS ADD PAIR (FROM PRMGroup, TO PRMResource);
    ALTER EDGE MEMBER_OF ADD PAIR (FROM AccountUser, TO PRMGroup);
    ALTER EDGE MEMBER_OF ADD PAIR (FROM PRMGroup, TO PRMGroup);
    ALTER EDGE MEMBER_OF ADD PAIR (FROM SecurityADGroup , TO PRMGroup);
    ALTER EDGE MEMBER_OF ADD PAIR (FROM PRMServiceAccount, TO PRMGroup);
}
END
RUN SCHEMA_CHANGE JOB prmEdgeTest

Produces these messages:

Semantic Check Fails: Adding Edge Pairs is currently not supported.
Please drop the edge and recreate it with the necessary Edge Pairs.

This post: Can't seem to alter either a vertex or an edge seems to be very similar. The issue there was described as due to use of a developer edition which does not support this.

I am using the Enterprise Free Edition - Free License. Is this capability disallowed with this license (thought the Enterprise license did not have capability limitations)? Or am I just doing something incorrectly?