Refresh Api not working as expected

I have a powershell script to publish and refresh Power BI reports. One of the calls being made is 

$refreshuri = "https://api.powerbi.com/v1.0/myorg/groups/$GroupId/datasets/$DatasetId/refreshes"

$SecondApiRequestBody = @"
    {
        "type": "ClearValues",
        "NotifyOption": "NoNotification
    }
"@ 
$null = Invoke-RestMethod -Uri $refreshuri -Headers $headers -Method POST -Body ("$SecondApiRequestBody")  -Verbose

The call is made successfully, however, the data in dataset partitions are not cleared. 

Any thoughts on why this could be the reason?