SharePoint lists open default forms

Target SharePoint environment

SharePoint Online

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

💥 SharePoint Framework

Developer environment

Windows

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

• browser version
• SPFx version
• Node.js version
• etc

Describe the bug / error

The list has a form SPFx extension. It is deployed via the content type property (such as NewFormClientSideComponentId). Starting Friday on some tenants the lists ignore the property and open the default form. Was there a recent rollout that is causing the bug?

Steps to reproduce

Only causes issues on some tenants

1. Deploy a form customizer SPFx solution
2. Set the component ID to the NewFormClientSideComponentId of the list content type
3. Open New form. It opens the default list form instead of the form customizer form.

Expected behavior

Open the form customizer form from the solution. It has worked for many years with no issues.

Start with the SharePoint Online form customizer deployment described in the issue, especially the content type's NewFormClientSideComponentId and the affected tenant behavior. Reproduce the steps in Edge or Chrome and compare tenants where the custom form opens with those where the default form opens. Done means identifying the rollout or documenting a confirmed cause and workaround.