Custom Cron Expression Automatically Overwritten

[mercy-ship-it]

Description

When a custom cron expression is entered in the Cron Trigger form, the value changes automatically after you leave the input field. For example, entering */8 * * * * is converted to Every 5 minutes, which is incorrect.

After saving and reopening the Cron Trigger, the custom cron field is no longer visible, and the form shows the incorrect auto-generated frequency instead.

Steps to Reproduce

1. Add a Cron Trigger.
2. Set Frequency to Custom.
3. Enter */8 * * * *.
4. Click outside the input field.
5. The form updates itself to Every N minutes → Every 5 minutes.
6. Save and reopen the Cron Trigger.
7. The custom cron expression is missing, and incorrect values are shown.

Expected Behavior

• The custom cron expression should remain exactly as entered.
• The form should not convert or override custom values.
• When reopening the panel, Custom should still be selected with the cron expression visible.

Actual Behavior

-The system actually runs the cron exactly as you set it . for example, if you choose every 8 minutes, it really does run every 8 minutes.

-The confusing part is the frontend display, which shows a different schedule even though the backend understood your cron correctly. Basically, the UI doesn't keep or show the original cron expression, so it looks like it changed even though it didn’t.

Screen.Recording.2025-11-18.at.18.23.02.mov

[mercy-ship-it]

cc @lmac-1

[lmac-1]

Hey @mercy-ship-it, I would perhaps tweak the wording here (for actual behaviour section)

The system changes the custom cron expression to a different schedule.
The original value is lost.

The system understands the custom cron expression - it's the way that we are displaying to the user that is a bit confusing.

What I mean is, if I set the custom cron expression to trigger every 8 minutes, the system will correctly trigger every 8 minutes. But, the way we represent this in the frontend is confusing and needs to change.

[mercy-ship-it]

Hey @lmac-1 This is updated

[doc-han]

findings: This is happening because our cron forms allow specific input values.
eg. Every N minutes allows users to pick 5mins, 10mins 15mins, 20mins & 30mins.
Hence entering any of these values as your custom cron will show up just as expected */20 * * * *. anything N minutes out of these values will fail to be rendered by the forms(select inputs for minutes) */8 * * * *. Instead of them to fallback to custom, it still just remains on the Every N select input, picking the first valid default option. 5mins.

[doc-han]

Don't we need a cron parser to make sure custom cron expressions are valid? eg. not allowing >60minutest to be entered which will be invalid