diff --git a/src/shared/automation-schedules.test.ts b/src/shared/automation-schedules.test.ts
index 5ff4ebec73b..0a867c52e4b 100644
--- a/src/shared/automation-schedules.test.ts
+++ b/src/shared/automation-schedules.test.ts
@@ -200,6 +200,34 @@ describe('automation schedules', () => {
     expect(isValidAutomationSchedule('0 9 * * 1-7')).toBe(true)
   })
 
+  it('runs a bare start value with a step through the end of its field', () => {
+    // Why: `5/15` is the shorthand every cron editor and Quartz read as
+    // "from 5, every 15" — 5,20,35,50. Dropping the step silently turned it
+    // into a single value, so the automation ran hourly instead.
+    const anchor = new Date('2026-05-01T00:00:00').getTime()
+    const runs: number[] = []
+    let cursor = anchor
+    for (let index = 0; index < 4; index += 1) {
+      const next = nextAutomationOccurrenceAfter('5/15 * * * *', anchor, cursor)
+      if (next === null) {
+        break
+      }
+      runs.push(new Date(next).getMinutes())
+      cursor = next
+    }
+
+    expect(runs).toEqual([5, 20, 35, 50])
+    // A bare value with no step still means exactly that value.
+    expect(new Date(nextAutomationOccurrenceAfter('5 * * * *', anchor, anchor)!).getMinutes()).toBe(
+      5
+    )
+    // `1/2` in day-of-week is Mon/Wed/Fri/Sun, matching `1-7/2`.
+    expect(isValidAutomationSchedule('0 9 * * 1/2')).toBe(true)
+    expect(nextAutomationOccurrenceAfter('0 9 * * 1/2', anchor, anchor)).toBe(
+      nextAutomationOccurrenceAfter('0 9 * * 1-7/2', anchor, anchor)
+    )
+  })
+
   it('rejects cron fields with malformed separators', () => {
     expect(isValidAutomationSchedule('*/15/2 9 * * *')).toBe(false)
     expect(isValidAutomationSchedule('0 9 1--5 * *')).toBe(false)
diff --git a/src/shared/automation-schedules.ts b/src/shared/automation-schedules.ts
index d8a93499287..e4331361501 100644
--- a/src/shared/automation-schedules.ts
+++ b/src/shared/automation-schedules.ts
@@ -150,7 +150,11 @@ function parseCronField(args: {
       end = parseCronNumber(endPart, args.names ?? null, args.field)
     } else {
       start = parseCronNumber(rangePart, args.names ?? null, args.field)
-      end = start
+      // Why: `5/15` is the shorthand for `5-<max>/15` that Quartz and every cron
+      // editor read as "from 5, every 15". Ending at `start` kept the value and
+      // dropped the step, which no cron dialect does — the automation then ran
+      // once per field cycle instead of on the interval the user wrote.
+      end = stepPart === undefined ? start : args.max
     }
 
     const normalizedStart = args.normalize?.(start) ?? start