diff --git a/src/modules/Elsa.Workflows.Core/Serialization/Converters/PolymorphicObjectConverter.cs b/src/modules/Elsa.Workflows.Core/Serialization/Converters/PolymorphicObjectConverter.cs
index 49eeeb940..f8121b24d 100644
--- a/src/modules/Elsa.Workflows.Core/Serialization/Converters/PolymorphicObjectConverter.cs
+++ b/src/modules/Elsa.Workflows.Core/Serialization/Converters/PolymorphicObjectConverter.cs
@@ -93,9 +93,9 @@ public class PolymorphicObjectConverter(IWellKnownTypeRegistry wellKnownTypeRegi
         if (isDictionary)
         {
             // Remove the _type property name from the JSON, if any.
-            var parsedModel = (JsonObject)JsonNode.Parse(ref reader)!;
-            parsedModel.Remove(TypePropertyName);
-            return parsedModel.Deserialize(targetType, newOptions)!;
+            var parsedNode = JsonNode.Parse(ref reader)!;
+            if (parsedNode is JsonObject parsedModel) parsedModel.Remove(TypePropertyName);
+            return parsedNode.Deserialize(targetType, newOptions)!;
         }
 
         var isCollection = typeof(ICollection).IsAssignableFrom(targetType);
@@ -247,7 +247,7 @@ public class PolymorphicObjectConverter(IWellKnownTypeRegistry wellKnownTypeRegi
             {
                 var typeOptions = newOptions.Clone();
                 typeOptions.Converters.RemoveWhere(c => c.GetType() != typeof(TypeJsonConverter));
-                
+
                 if (typeOptions.Converters.Any())
                 {
                     var typeValue = JsonSerializer.Serialize(type, typeOptions).Trim('"');
@@ -265,6 +265,9 @@ public class PolymorphicObjectConverter(IWellKnownTypeRegistry wellKnownTypeRegi
 
     private Type? ReadType(Utf8JsonReader reader)
     {
+        if (reader.TokenType != JsonTokenType.StartObject)
+            return null;
+
         reader.Read(); // Move to the first token inside the object.
         string? typeName = null;