diff --git a/src/modules/Elsa.Workflows.Core/Serialization/Converters/TypeJsonConverter.cs b/src/modules/Elsa.Workflows.Core/Serialization/Converters/TypeJsonConverter.cs
index 816b5fb5b..5fe74064e 100644
--- a/src/modules/Elsa.Workflows.Core/Serialization/Converters/TypeJsonConverter.cs
+++ b/src/modules/Elsa.Workflows.Core/Serialization/Converters/TypeJsonConverter.cs
@@ -40,9 +40,9 @@ public class TypeJsonConverter : JsonConverter<Type>
         }
         
         // Handle collection types.
-        if (typeAlias.EndsWith("()"))
+        if (typeAlias.StartsWith("List<") && typeAlias.EndsWith(">"))
         {
-            var elementTypeAlias = typeAlias[..^"()".Length];
+            var elementTypeAlias = typeAlias[5..^1];
             var elementType = _wellKnownTypeRegistry.TryGetType(elementTypeAlias, out var t) ? t : Type.GetType(elementTypeAlias)!;
             return typeof(List<>).MakeGenericType(elementType);
         }
@@ -70,7 +70,7 @@ public class TypeJsonConverter : JsonConverter<Type>
 
             if (typedEnumerable.IsAssignableFrom(value) && _wellKnownTypeRegistry.TryGetAlias(elementType, out var elementTypeAlias))
             {
-                writer.WriteStringValue($"{elementTypeAlias}()");
+                writer.WriteStringValue($"List<{elementTypeAlias}>");
                 return;
             }
         }
diff --git a/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs b/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs
index 2524822c9..37899fc1b 100644
--- a/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs
+++ b/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs
@@ -59,7 +59,7 @@ public class VariableMapper
             .OnSuccess(value => variable.Value = value)
             .OnFailure(e => _logger.LogWarning("Failed to convert {SourceValue} to {TargetType}", source.Value, type.Name));
 
-        variable.StorageDriverType = !string.IsNullOrEmpty(source.StorageDriverTypeName) ? Type.GetType(source.StorageDriverTypeName) : default;
+        variable.StorageDriverType = !string.IsNullOrEmpty(source.StorageDriverTypeName) ? Type.GetType(source.StorageDriverTypeName) : null;
 
         return variable;
     }
@@ -76,6 +76,6 @@ public class VariableMapper
         var storageDriverTypeName = source.StorageDriverType?.GetSimpleAssemblyQualifiedName();
         var serializedValue = value.Format();
 
-        return new VariableModel(source.Id, source.Name, valueTypeAlias, serializedValue, storageDriverTypeName);
+        return new(source.Id, source.Name, valueTypeAlias, serializedValue, storageDriverTypeName);
     }
 }
\ No newline at end of file