diff --git a/packages/core/src/NodeExecuteFunctions.ts b/packages/core/src/NodeExecuteFunctions.ts
index cac599b5ca..ca1ea6028b 100644
--- a/packages/core/src/NodeExecuteFunctions.ts
+++ b/packages/core/src/NodeExecuteFunctions.ts
@@ -33,6 +33,7 @@ import { Agent, type AgentOptions } from 'https';
 import get from 'lodash/get';
 import isEmpty from 'lodash/isEmpty';
 import pick from 'lodash/pick';
+import { DateTime } from 'luxon';
 import { extension, lookup } from 'mime-types';
 import type {
 	BinaryHelperFunctions,
@@ -2096,7 +2097,7 @@ export async function getCredentials(
  * Clean up parameter data to make sure that only valid data gets returned
  * INFO: Currently only converts Luxon Dates as we know for sure it will not be breaking
  */
-function cleanupParameterData(inputData: NodeParameterValueType): void {
+export function cleanupParameterData(inputData: NodeParameterValueType): void {
 	if (typeof inputData !== 'object' || inputData === null) {
 		return;
 	}
@@ -2107,14 +2108,15 @@ function cleanupParameterData(inputData: NodeParameterValueType): void {
 	}
 
 	if (typeof inputData === 'object') {
-		Object.keys(inputData).forEach((key) => {
-			if (typeof inputData[key as keyof typeof inputData] === 'object') {
-				if (inputData[key as keyof typeof inputData]?.constructor.name === 'DateTime') {
+		type Key = keyof typeof inputData;
+		(Object.keys(inputData) as Key[]).forEach((key) => {
+			const value = inputData[key];
+			if (typeof value === 'object') {
+				if (value instanceof DateTime) {
 					// Is a special luxon date so convert to string
-					inputData[key as keyof typeof inputData] =
-						inputData[key as keyof typeof inputData]?.toString();
+					inputData[key] = value.toString();
 				} else {
-					cleanupParameterData(inputData[key as keyof typeof inputData]);
+					cleanupParameterData(value);
 				}
 			}
 		});
diff --git a/packages/core/test/NodeExecuteFunctions.test.ts b/packages/core/test/NodeExecuteFunctions.test.ts
index 13791d126c..a644cd6793 100644
--- a/packages/core/test/NodeExecuteFunctions.test.ts
+++ b/packages/core/test/NodeExecuteFunctions.test.ts
@@ -1,4 +1,5 @@
 import {
+	cleanupParameterData,
 	copyInputItems,
 	getBinaryDataBuffer,
 	parseIncomingMessage,
@@ -7,6 +8,7 @@ import {
 	removeEmptyBody,
 	setBinaryDataBuffer,
 } from '@/NodeExecuteFunctions';
+import { DateTime } from 'luxon';
 import { mkdtempSync, readFileSync } from 'fs';
 import type { IncomingMessage } from 'http';
 import { mock } from 'jest-mock-extended';
@@ -18,6 +20,7 @@ import type {
 	IRequestOptions,
 	ITaskDataConnections,
 	IWorkflowExecuteAdditionalData,
+	NodeParameterValue,
 	Workflow,
 	WorkflowHooks,
 } from 'n8n-workflow';
@@ -414,6 +417,29 @@ describe('NodeExecuteFunctions', () => {
 		});
 	});
 
+	describe('cleanupParameterData', () => {
+		it('should stringify Luxon dates in-place', () => {
+			const input = { x: 1, y: DateTime.now() as unknown as NodeParameterValue };
+			expect(typeof input.y).toBe('object');
+			cleanupParameterData(input);
+			expect(typeof input.y).toBe('string');
+		});
+
+		it('should handle objects with nameless constructors', () => {
+			const input = { x: 1, y: { constructor: {} } as NodeParameterValue };
+			expect(typeof input.y).toBe('object');
+			cleanupParameterData(input);
+			expect(typeof input.y).toBe('object');
+		});
+
+		it('should handle objects without a constructor', () => {
+			const input = { x: 1, y: { constructor: undefined } as unknown as NodeParameterValue };
+			expect(typeof input.y).toBe('object');
+			cleanupParameterData(input);
+			expect(typeof input.y).toBe('object');
+		});
+	});
+
 	describe('copyInputItems', () => {
 		it('should pick only selected properties', () => {
 			const output = copyInputItems(