diff --git a/geoengine/workflow_builder/operators.py b/geoengine/workflow_builder/operators.py
index ca085b09..00dcac5a 100644
--- a/geoengine/workflow_builder/operators.py
+++ b/geoengine/workflow_builder/operators.py
@@ -693,7 +693,7 @@ def from_operator_dict(cls, operator_dict: Dict[str, Any]) -> 'Expression':
             raise ValueError("Invalid operator type")
 
         output_band = None
-        if "outputBand" in operator_dict["params"] and operator_dict["params"] is not None:
+        if "outputBand" in operator_dict["params"] and operator_dict["params"]["outputBand"] is not None:
             output_band = RasterBandDescriptor.from_response(
                 geoengine_openapi_client.RasterBandDescriptor.from_dict(
                     operator_dict["params"]["outputBand"]