Missing data when filter predicate is removed

[Sree]

Hi Gurus,
I have the below request body for a POST call to the Aggregate Queries api - https://api.mypurecloud.de/api/v2/analytics/conversations/aggregates/query

 {
     "interval": "2023-01-16T00:00:00Z/2023-01-18T00:00:00Z",
     "granularity": "PT15M",
     "groupBy": [
         "activeSkillId",
         "direction",
         "divisionId",
         "dnis",
         "edgeId",
         "mediaType",
         "queueId"
     ],
     "filter": {
         "type": "and",
         "predicates": [
             {
                 "type": "dimension",
                 "dimension": "queueId",
                 "operator": "exists",
                 "value": None
             },
             {
                 "type": "dimension",
                 "dimension": "divisionId",
                 "operator": "matches",
                 "value": "66a65635-ca81-483a-a730-xxxxxxxxxxxx"
             },
             {
                 "type": "dimension",
                 "dimension": "requestedRoutingSkillId",
                 "operator": "matches",
                 "value": "6ddd1266-4bc6-4e61-b43a-xxxxxxxxxxx"
             }
         ]
     },
         "metrics": [
         "tFlowOut"
     ],
     "flattenMultivaluedDimensions": True
 }

Note - The filter contains the predicate for the dimension requestedRoutingSkillId. I receive tFlowOut data for this request.

However, when I remove the filter for the dimension requestedRoutingSkillId, I receive no tFlowOut data for this SkillID at all.
Any ideas why removing the filter results in not getting the data in response.

What is more confusing is that for another interval, I receive the data for this requestedRoutingSkillId even when filter is not applied.

Kindly help with you inputs.