attributed_message not working?

I am using API revision 2024-02-15.

If I do a post to https://a.klaviyo.com/api/metric-aggregates/ and I pass it the following json object in the body, it behaves as if I did not include the “by” command and does not aggregate by campaign but just gives it as if I did not specify the by.

{  
     "data": {  
          "type": "metric-aggregate",  
          "attributes": {  
               "measurements": [  
                    "count", "unique"  
               ],  
               "filter": [  
                    "greater-or-equal(datetime,2024-01-01),less-than(datetime,2024-12-31)"
               ],  
               "by": ["$attributed_message"],  
               "interval": "month",  
               "timezone": "US/Eastern",  
               "metric_id": "WhateverMetric_IdUsed"  
          }  
     }  
}

Similarly, if in the filter I indicate the campaign I wish to see, it returns nothing at all.

               "filter": [  
                    "greater-or-equal(datetime,2024-01-01),less-than(datetime,2024-12-31)",  
                    "equals($attributed_message,\"SOME_CAMPAIGN_ID\")"  
               ],  
 

isn’t $attributed_message the property to use for CampaignIds?