chore(core): Send a telementry event if a node outputs non json data (#16558)

Co-authored-by: Danny Martini <danny@n8n.io>

packages/core/src/execution-engine/workflow-execute.ts

@@ -61,6 +61,7 @@ import PCancelable from 'p-cancelable';
 import { ErrorReporter } from '@/errors/error-reporter';
 import { WorkflowHasIssuesError } from '@/errors/workflow-has-issues.error';
 import * as NodeExecuteFunctions from '@/node-execute-functions';
+import { isJsonCompatible } from '@/utils/is-json-compatible';
 
 import { ExecuteContext, PollContext } from './node-execution-context';
 import {
@@ -1193,6 +1194,27 @@ export class WorkflowExecute {
 						: await nodeType.execute.call(context);
 			}
 
+			// If data is not json compatible then log it as incorrect output
+			// Does not block the execution from continuing
+			const jsonCompatibleResult = isJsonCompatible(data);
+			if (!jsonCompatibleResult.isValid) {
+				Container.get(ErrorReporter).error(
+					new UnexpectedError('node execution output incorrect data'),
+					{
+						extra: {
+							nodeName: node.name,
+							nodeType: node.type,
+							nodeVersion: node.typeVersion,
+							workflowId: workflow.id,
+							workflowName: workflow.name ?? 'Unnamed workflow',
+							executionId: this.additionalData.executionId ?? 'unsaved-execution',
+							errorPath: jsonCompatibleResult.errorPath,
+							errorMessage: jsonCompatibleResult.errorMessage,
+						},
+					},
+				);
+			}
+
 			const closeFunctionsResults = await Promise.allSettled(
 				closeFunctions.map(async (fn) => await fn()),
 			);