UPD: My issue was not related to the previously reported bug, so I would consider it fixed. The reason of my problem was that in one place I forgot to modelContext.save() before sending model container to the ModelActor and possibly there was some conflict.

If I click on this I get 'Feedback not found' 🤔

UPDATE: Apple engineer confirmed it's a bug and offered a workaround here using NotificationCenter. Tested it in my project and it worked, the UI updates are triggered correctly.