Rails - adding nested attributes then validation fails, new nested attributes are not passed back to the :edit render

I have a Rails app with nested attributes. My MVC works great except when the nested validation fails. Here is my parent model controller:

    def update

        if @model.update(model_params)

            respond_to do |format|
                format.html { redirect_to @model, notice: 'Model was successfully updated.'}
            end

        else
            render :edit
        end
    end

The issue is then in my model view when I build the nested form again:

<%= f.simple_fields_for :nested_model, @model.nested_model.joins(:related_model).order(:name)  do |i| %>

I get all the original nested_model items in the form but the new ones that were passed in the params are not added. This works 100% when there are no validation issues. How do I add those invalid nested_model items back in here. I feel like there is an existing solution to this that I can't seem to find easily.

Eliminating the @model.nested_model.joins(:related_model).order(:name) did the trick.