fix(core): Scheduler tasks should not trigger on follower instances (#10507)

packages/core/src/ScheduledTaskManager.ts

@@ -1,13 +1,24 @@
 import { Service } from 'typedi';
 import { CronJob } from 'cron';
 import type { CronExpression, Workflow } from 'n8n-workflow';
+import { InstanceSettings } from './InstanceSettings';
 
 @Service()
 export class ScheduledTaskManager {
+	constructor(private readonly instanceSettings: InstanceSettings) {}
+
 	readonly cronJobs = new Map<string, CronJob[]>();
 
 	registerCron(workflow: Workflow, cronExpression: CronExpression, onTick: () => void) {
-		const cronJob = new CronJob(cronExpression, onTick, undefined, true, workflow.timezone);
+		const cronJob = new CronJob(
+			cronExpression,
+			() => {
+				if (this.instanceSettings.isLeader) onTick();
+			},
+			undefined,
+			true,
+			workflow.timezone,
+		);
 		const cronJobsForWorkflow = this.cronJobs.get(workflow.id);
 		if (cronJobsForWorkflow) {
 			cronJobsForWorkflow.push(cronJob);