Turbo:render fired twice (not a cached preview) when following redirect_to triggered by Turbo link with frame '_top'

Let’s have a method called show_a in the first controller and method show_b in the second controller that look like this:

# first_controller.rb
class FirstController < ApplicationController
  def show_a
    render :show

# second_controller.rb
class SecondController < ApplicationController
  def show_b

Then when I navigate to route for the first_controller#show_a everything works as expected. But when I navigate to the second_controller#show_b using Turbo link with data-turbo-frame="_top" the turbo:render and other events are fired twice and neither of them is for the cached preview. It also initializes my Stimulus controllers twice.

Any ideas what could cause that please?