InvariantError when the "ai" feature is only allowed on some fields on a page

[JNaftali]

Issue summary

https://reactjs.org/docs/error-decoder.html?invariant=321 when the "ai" feature is present in some but not all draftail editors on a page.

Steps to reproduce

1. Start a new project with wagtail start myproject and set up wagtail-ai
2. add a page type with a RichTextField(features=[]) and a streamfield containing a RichTextBlock(features=["ai"])
3. migrate, create a page with that type
4. The editor loads fine initially, but adding a RichTextBlock to the streamfield causes draftail to crash

Additional information

No response

Can be reproduced

Not confirmed

Technical details

• uv run python --version
  Python 3.14.0
• uv pip list | grep wagtail
  wagtail 7.4.1
  wagtail-ai 3.1.0
• uv pip list | grep django
  django 5.2.14

Working on this

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[JNaftali]

Attaching a minimal repro here - https://github.com/JNaftali/wagtail-ai-165-repro

[thibaudcolas]

thank you, can reproduce! The code in the package looks fine, there’s a good chance this is surfacing an issue in Wagtail itself. Will investigate.