Cypress opening new tabs causes cookies to be introduced into subsequent tests

Cookies are seemingly coming out of nowhere causing independent tests to fail.

Installing

git clone https://github.com/Qarj/cypress-test-tiny.git
cd cypress-test-tiny
npm i

npx cypress open

Double click on cookieBug.js.

In the file cypress/integration/cookieBug.js comment out the line

    causeBug();

and run again, all tests should run ok.

The application under test opens up new browser tabs on clicking the applicable elements.

We set up a spy to check that the redirect url for the new tabs is fired and is correct.

This test passes perfectly fine everytime.

However the subsequent tests are getting poisoned by cookies from these new tabs.

What appears to happen is this:

Test 1 ends as soon as it has validated the redirect
Test 2 now starts
Meanwhile, the new tabs left over from test 1 continue to load and create cookies
These new cookies end up appearing in Test 2

My understanding of Cypress is that it cannot control anything in the new browser tabs due to being stuck in a security sandbox.

However the reverse does not appear to be true - these detached tabs / windows can affect Cypress!