I have a resource TodoTask that has a many-to-many with a Context like so

# in todo_task
    relationships do
      has_many :context_relationships, TodoTaskContext do
        destination_attribute :task_id
      end

      many_to_many :contexts, Context do
        join_relationship :context_relationships
        source_attribute_on_join_resource :task_id
        destination_attribute_on_join_resource :context_id
      end
    end

I’m trying to set up the form and change so that all existing Contexts are listed as checkboxes, and when the form is submitted, there will be a TodoTaskContext created for this TodoTask and Context. I have this working correctly in a unit test with a manage_relationship that looks like this:

  # in todo_task
     update :update do
        accept ...
        argument :contexts, {:array, :string}, allow_nil?: true, default: []
        require_atomic? false

        change manage_relationship(:contexts, :context_relationships,
                 value_is_key: :context_id,
                 type: :direct_control
               )
      end

and I’m creating a form in my LV like so

AshPhoenix.Form.for_update(task, :update, as: "task")

But the related contexts aren’t being loaded. When I log out my @form[:contexts], the value is always an empty list.

%{
  id: "task_contexts",
  name: "task[contexts]",
  value: [],
  __struct__: Phoenix.HTML.FormField,
  field: :contexts,
  errors: []
}

I’ve made sure my relationships are loaded just before creating AshPhoenix.Form.for_update, but that doesn’t seem to change anything:

    task = task |> Ash.load!([:contexts, :context_relationships])

Is there something wrong with how I’ve got my manage_relationship set up? Or is there something else I need to add?

Thanks!