Testing CI without mountable_engine? stub that leaking to other specs

Other specs always refere to mountable_engine?

Like:
  99) Rspec::Generators::ScaffoldGenerator standard controller spec with --controller_specs
      Failure/Error: before { run_generator %w[posts --controller_specs] }

      Thor::UndefinedCommandError:
        Could not find command "mountable_engine?".

Like if the stub was leaking

spec/generators/rspec/scaffold/scaffold_generator_spec.rb

@@ -40,7 +40,7 @@
       it { is_expected.to contain('renders a JSON response with errors for the post') }
     end
 
-    describe 'in an engine' do
+    xdescribe 'in an engine' do
       before do
         allow_any_instance_of(::Rails::Generators::NamedBase).to receive(:mountable_engine?).and_return(true)
         run_generator %w[posts --request_specs]