Aggregate item definition:
Source item definition:
The user macro contents are also identical on the aggregate host and the source hosts, which are in the group "Cluster: Postgres/GEN/test".
The group name matches and all source items have valid values, but all aggregate items are 'not supported' with an error like this.
That "%s" in the error message should probably expand to something useful, but is the issue just one of error message parameter expansion or is it really comparing the key to a literal "%s" string and failing because of that..?