Story Points field editable in UI but not on screen — unexpected behavior

I’m a bit confused and hoping someone can clarify the behavior I’m seeing.

In my Jira Software project, the Story Points field is visible on the Issue View, and I can edit it via the UI without any issues. However, when I try to update the same field using the REST API, I receive the following error:

"Field 'customfield_10036' cannot be set. It is not on the appropriate screen, or unknown."

After some investigation, I discovered that while the field was visible on the Issue Layout, it was missing from the Screen configuration. Once I added it to the screen, the REST API call worked as expected.

This made me question how the Issue Layout and Screen configurations could become unsynchronized. Until now, I was under the impression that adding or removing a field via the Issue Layout would automatically update the corresponding screen, and vice versa. I tested this with a regular custom number field, and that assumption still holds true.

However, this doesn’t seem to apply to the Story Points field.

A few additional observations:

  • The Story Points field in my instance is of type: com.atlassian.jira.plugin.system.customfieldtypes:float (not the older com.pyxis.greenhopper.jira:jsw-story-points).
  • When I remove Story Points from the screen, it remains editable in the Issue View.
  • In a fresh Software project created from the default template, the Story Points field appears on the Issue Layout even though it’s not present on the screen.

So, my question is:
How is it possible that I can edit a field in the UI if it’s not present on the Edit screen?
Is this a special case for Story Points, or is there some underlying logic in how Jira handles this field differently?

Any insights would be appreciated. Thanks!

The UI Modification API for the Story Points field on the Issue View also doesn’t work as expected: Jira