How to use quantiles on a 2d data cube (x,y)

Hi @stefaan.lippens, thanks for the direct support!
I’ve adapted the process graph to include the array_element process as suggested.
I get a different error now.

PG:

{
  "process_graph": {
    "aggregate1": {
      "arguments": {
        "data": {
          "from_node": "load1"
        },
        "geometries": {
          "coordinates": [
            [
              [
                11.405728030894776,
                47.34336009384771
              ],
              [
                11.336232816497366,
                47.34336009384771
              ],
              [
                11.336232816497366,
                47.3831235941382
              ],
              [
                11.405728030894776,
                47.3831235941382
              ],
              [
                11.405728030894776,
                47.34336009384771
              ]
            ]
          ],
          "type": "Polygon"
        },
        "reducer": {
          "process_graph": {
            "array1": {
              "arguments": {
                "data": {
                  "from_node": "quantiles1"
                },
                "index": 0
              },
              "process_id": "array_element",
              "result": true
            },
            "quantiles1": {
              "arguments": {
                "data": {
                  "from_parameter": "data"
                },
                "probabilities": [
                  0.5
                ]
              },
              "process_id": "quantiles"
            }
          }
        }
      },
      "process_id": "aggregate_spatial"
    },
    "load1": {
      "arguments": {
        "id": "COPERNICUS_30",
        "spatial_extent": {
          "east": 11.433438104703031,
          "north": 47.411132815621606,
          "south": 47.28888805806898,
          "west": 11.285468923538287
        },
        "temporal_extent": [
          "2010-12-12T00:00:00Z",
          null
        ]
      },
      "process_id": "load_collection"
    },
    "save3": {
      "arguments": {
        "data": {
          "from_node": "aggregate1"
        },
        "format": "CSV"
      },
      "process_id": "save_result",
      "result": true
    }
  }
}

ID: j-2403075b05aa4d7095e3356f0f263653

Error:

OpenEO batch job failed: java.lang.IllegalArgumentException: The process Constants are not expected in a reducer callback, got value 0.5. is not supported to be used in a reducer callback.
+50s 256msERROR
ID: [1709808964929, 932882]
▸
OpenEO batch job failed: java.lang.IllegalArgumentException: The process Constants are not expected in a reducer callback, got value 0.5. is not supported to be used in a reducer callback.
+2m 13s 936msERROR
ID: [1709809048609, 135653]

I have also tried passing two probabilities to quantiles, like [0.5, 0.75], it results in the same error, but only one of the identical error messages.