You might encounter it when upgrading to rails >= 7.

There is a breaking change in Rails 7: Invalid form submissions have to return a 422 status code for Turbo Drive to replace the <body> of the page and display the form errors. The alias for the 422 status code in Rails is :unprocessable_entity. That’s why, since Ruby on Rails 7, the scaffold generator adds status: :unprocessable_entity to #create and #update actions when the resource couldn’t be saved due to an invalid form submission.

It is all about adding status: :unprocessable_entity in else

def create
  @quote = Quote.new(quote_params)
  
  if @quote.save
    redirect_to quotes_path, notice: "Quote was successfully created."
  else
    render :new, status: :unprocessable_entity
  end
end

No validation error messages and console error without status: :unprocessable_entity

Expected behavior with status: :unprocessable_entity

Source: Turbo Rails Tutorial

That's it for this post, thanks for reading!