Why is OCI monitoring namespace "oci_osms" not avaiable in Metrics Explorer?

Summary:

When I try to browse OS Management metrics in the Metrics Explorer I find that namespace "oci_osms" is not among the listed options. Very strange.

More so, if you visit the OS Management Metrics and Alarms page, you'll see metrics there and you can launch into Metrics Explorer but still "oci_osms" namespace isn't listed. However, if you note the URL, you'll see that namespace=oci_osms is present (which is apparently why the Metrics Explorer will show OSMS metrics if and only if launched from the OSMS Metrics page). Bug it seems?

Content (required):

When I try to browse OS Management metrics in the Metrics Explorer I find that namespace "oci_osms" is not among the listed options. Very strange.