right

{
    "image": {
        "__flow_object_type": "TYPO3\\Media\\Domain\\Model\\ImageVariant",
        "__identifier": "7dac7063-db28-d7c7-a8f0-383a3f0aec3e"
    },
}

wrong

{    
    "image": {
        "0": "{\"__identity\":\"e3f0bc9a-a20e-2328-221f-0b4e52fa148d\",\"__type\":\"TYPO3\\\\Media\\\\Domain\\\\Model\\\\ImageVariant\",\"adjustments\":{\"TYPO3\\\\Media\\\\Domain\\\\Model\\\\Adjustment\\\\CropImageAdjustment\":{\"height\":1154,\"position\":10,\"width\":2048,\"x\":0,\"y\":65},\"TYPO3\\\\Media\\\\Domain\\\\Model\\\\Adjustment\\\\ResizeImageAdjustment\":{\"height\":1153,\"maximumHeight\":null,\"maximumWidth\":null,\"minimumHeight\":null,\"minimumWidth\":null,\"position\":20,\"ratioMode\":null,\"width\":2048}}}",
        "1": "{\"__identity\":\"e3f0bc9a-a20e-2328-221f-0b4e52fa148d\",\"__type\":\"TYPO3\\\\\\\\Media\\\\\\\\Domain\\\\\\\\Model\\\\\\\\ImageVariant\",\"adjustments\":{\"TYPO3\\\\\\\\Media\\\\\\\\Domain\\\\\\\\Model\\\\\\\\Adjustment\\\\\\\\CropImageAdjustment\":{\"height\":1154,\"position\":10,\"width\":2048,\"x\":0,\"y\":65},\"TYPO3\\\\\\\\Media\\\\\\\\Domain\\\\\\\\Model\\\\\\\\Adjustment\\\\\\\\ResizeImageAdjustment\":{\"height\":1153,\"maximumHeight\":null,\"maximumWidth\":null,\"minimumHeight\":null,\"minimumWidth\":null,\"position\":20,\"ratioMode\":null,\"width\":2048}}}"
    },
}