Bad nested Aggregate failures reporting

[Startouf]

Given the following test

context 'with a sideloading request' do
        let(:user) { create(:user, :with_school, tag_count: 1}
        before(:each) do
          get profile_url(params: { include: [:school, :tags].join(',') })
        end

        it 'renders the sideloaded entities in the JSON' do
          expect(json_included_types).to include('school', 'tag')
          aggregate_failures('sideloaded entities') do
            assert_payload(:'public/school', user.school, json_include('school'))
            assert_payload(:'public/tag', user.tags.first, json_include('tag'))
          end
        end
      end
end

The output provided on the nested aggregate_failure > assert_payload is quite enigmatic

Got 2 failures and 1 other error from failure aggregation block "sideloaded entities".
     [Backtrace]
     1.1) Got 2 failures from failure aggregation block "payload has correct key/values".
          [Backtrace]
          1.1.1) Failure/Error: assign_backtrace(failure) unless failure.backtrace
                   Expected JSON payload to have key 'created_at' but was not present
                 [Backtrace]
          1.1.2) Failure/Error: assign_backtrace(failure) unless failure.backtrace
                   Expected JSON payload to have key 'updated_at' but was not present
                 [Backtrace]

The weird part here is

1.1.1) Failure/Error: assign_backtrace(failure) unless failure.backtrace

Whereas the usual error message should repeat the error line like
Failure/Error: assert_payload(:'public/school', user.school, json_include('school'))