Columns marked as readonly stopped appearing in edit row form

Target SharePoint environment

SharePoint Online

What SharePoint development model, framework, SDK or API is this about?

Declarative list formatting

Developer environment

None

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

• Microsoft Edge 146.0.3856.59

Describe the bug / error

I have configured input form for list. I used json body like so:

{
  "sections": [
    {
      "displayname": "Section 1",
      "fields": [
        "Feedback"
      ]
    }
  ],
  "fieldsettings": [
    {
      "name": "Feedback",
      "readonly": true
    }
  ]
}

When adding new item Feedback field doesn't appear which is expected behaviour. The problem is that this field doesn't appear when editing existing items too. The field type is number, it is not required and I have edited Feedback column as the only one that should appear in form. I am using correct internal name.

When I remove fieldsettings or set readonly to false field reappears as editable as expected.

This problem was not present 3 weeks ago. On the same form with the same json configuration.

Steps to reproduce

1. Set readonly to true in fieldsettings for some column in input form body json
2. Field disappears in editing

Expected behavior

The field should appear as (Read only) in edit mode like mentioned here https://learn.microsoft.com/en-us/sharepoint/dev/declarative-customization/list-form-configuration