From 86f47ee6dc88397b05bfb784b0092674ba3b4289 Mon Sep 17 00:00:00 2001
From: mfsiega <93014743+mfsiega@users.noreply.github.com>
Date: Fri, 1 May 2026 12:34:37 +0200
Subject: [PATCH] fix(Schedule Node): Cap day-of-month jitter at 28 (#29614)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 packages/nodes-base/nodes/Schedule/GenericFunctions.ts      | 4 +++-
 .../nodes-base/nodes/Schedule/test/GenericFunctions.test.ts | 6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/packages/nodes-base/nodes/Schedule/GenericFunctions.ts b/packages/nodes-base/nodes/Schedule/GenericFunctions.ts
index e312186b1e9..84e55a9e393 100644
--- a/packages/nodes-base/nodes/Schedule/GenericFunctions.ts
+++ b/packages/nodes-base/nodes/Schedule/GenericFunctions.ts
@@ -126,7 +126,9 @@ export const toCronExpression = (interval: ScheduleInterval, nodeKey: string): C
 		return `${second} ${minute} ${hour} * * ${daysOfWeek}` as CronExpression;
 	}
 
-	const dayOfMonth = interval.triggerAtDayOfMonth ?? stableInt(nodeKey, 'dayOfMonth', 1, 31);
+	// Cap at 29 (exclusive) so jitter yields 1-28: any higher day would silently
+	// skip months that don't contain it (e.g. day 30 skips February every year).
+	const dayOfMonth = interval.triggerAtDayOfMonth ?? stableInt(nodeKey, 'dayOfMonth', 1, 29);
 	return `${second} ${minute} ${hour} ${dayOfMonth} */${interval.monthsInterval} *`;
 };
 
diff --git a/packages/nodes-base/nodes/Schedule/test/GenericFunctions.test.ts b/packages/nodes-base/nodes/Schedule/test/GenericFunctions.test.ts
index 77d8cee86ec..d9a75e51761 100644
--- a/packages/nodes-base/nodes/Schedule/test/GenericFunctions.test.ts
+++ b/packages/nodes-base/nodes/Schedule/test/GenericFunctions.test.ts
@@ -33,7 +33,7 @@ function mockMomentTz(values: {
 // from the input interval.
 //
 // For `seed = 'test-key'`, `stableInt` produces:
-//   second=56, minute=19, hour=14, dayOfMonth=4
+//   second=56, minute=19, hour=14, dayOfMonth=22
 const TEST_SEED = 'test-key';
 
 describe('toCronExpression', () => {
@@ -158,7 +158,7 @@ describe('toCronExpression', () => {
 			TEST_SEED,
 		);
 		expect(result).toEqual('56 0 0 1 */3 *');
-		// Nothing pinned, so sec=56 / min=19 / hr=14 / dom=4 are all filler.
+		// Nothing pinned, so sec=56 / min=19 / hr=14 / dom=22 are all filler.
 		const result1 = toCronExpression(
 			{
 				field: 'months',
@@ -166,7 +166,7 @@ describe('toCronExpression', () => {
 			},
 			TEST_SEED,
 		);
-		expect(result1).toEqual('56 19 14 4 */3 *');
+		expect(result1).toEqual('56 19 14 22 */3 *');
 	});
 });